container

Abstract

To provide a container with an outer surface formed by a flat surface without any unevenness and with a continuous unevenness in a circumferential direction of an inner surface.SOLUTION: The container is characterized in that an outer surface is formed with a flat surface without any unevenness, and mountain-shaped raised parts and valley-shaped sedimentation parts smoothly connected without edges are alternately and continuously formed in a circumferential direction of an inner surface.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a container having portions with different wall thicknesses.

Background Art

[0002] A conventional direct blow molding apparatus includes: a parison forming die (hereinafter simply referred to as "die") that extrudes a molten thermoplastic resin into a tubular shape to form a parison; a core disposed at the center of the thermoplastic resin discharge opening of the die; and a container mold that clamps the parison in a state where one end of the formed parison is sealed, and expands the parison from the inside to form a container shape.

[0003] Further, in a conventional direct blow molding apparatus, an invention is disclosed in which grooves are formed in the core so that containers with different wall thicknesses in the circumferential direction of the container can be molded (see Patent Document 1). The grooves in this core form thick portions along the height direction on the inner surface of the parison extruded from the die by the grooves of the core. Then, by placing this parison into the aforementioned container mold and expanding the parison into the shape of the container, a container with different wall thicknesses in the circumferential direction of the inner surface is formed.

[0004] However, in the conventional direct blow molding apparatus, although it is possible to form ribs (protrusions) in the height direction on the inner surface of the container to achieve different wall thicknesses in the circumferential direction, it is not possible to manufacture a container having circumferentially continuous irregularities on the inner surface of the container, and no such concept ever existed. Furthermore, no container having circumferentially continuous irregularities on the inner surface of the container has ever existed.

[0005] In addition, when forming irregularities on the outer surface side of the container, the irregularities can be easily formed by making the container mold that clamps the parison into a shape with irregularities, but it has not been possible to form a container having irregularities on the inner surface side or a container with different wall thicknesses.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] Therefore, the inventors of the present invention diligently conducted research to form irregularities in the circumferential direction on the inner surface of a container, and after much trial and error, they arrived at the present invention. The present invention was made in view of these points, and one of its objectives is to provide a container having irregularities in the circumferential direction on its inner surface. [Means for solving the problem]

[0008] A method for manufacturing a container according to one aspect of the present invention comprises the steps of: step A, forming a tubular parison having irregularities on its outer surface; step B, sandwiching the parison with a mold; and step C, inflating the parison from the inside to form a container, wherein in step A, the opening of the die from which the resin is extruded has an irregular shape on its outer circumference, and as the resin is extruded from the die, a parison having irregularities on its outer surface is formed, and irregularities are formed on the inner surface of the container formed through step C.

[0009] In this configuration, the resin forming the parison is extruded from a die having irregularities on the outer circumference of the opening, thereby forming a parison with irregularities on its outer surface. As a result, the thickness of the extruded parison varies in the circumferential direction, and by inflating the parison from the inside with air or the like while it is sandwiched in a mold, it becomes possible to form irregularities on the inner surface of the container. The irregularities formed by this manufacturing method are formed in the circumferential direction, and the recessed parts (sedimented parts) and convex parts (raised parts) are smoothly continuous.

[0010] Furthermore, in step A of this container manufacturing method, the opening of the die is characterized in that recesses and protrusions are alternately connected in a continuous manner in the circumferential direction. With this configuration, it is possible to manufacture a container in which recesses and protrusions are alternately connected in a continuous manner in the circumferential direction of the inner surface.

[0011] Furthermore, the method for manufacturing this container is characterized in that, in step A, the opening of the die is formed in a gear shape. With this configuration, the container can have a gear-shaped cross-section, and the inner surface has alternating concave and convex portions in the circumferential direction.

[0012] Furthermore, in the manufacturing method of this container, in step A, the opening of the die is characterized in that the recess and the protrusion are smoothly connected. With this configuration, a container can be made in which the recess and the protrusion are smoothly connected in the circumferential direction of the inner surface.

[0013] Furthermore, in the manufacturing method of this container, in step A, a core is inserted through the center of a through hole communicating with the opening of the die, and resin is extruded from the gap between the opening of the die and the core, forming a tubular parison with varying wall thicknesses in the circumferential direction.

[0014] Furthermore, the method for manufacturing this container is characterized in that, in step C, the parison sandwiched in the mold is inflated with air from the inside, thereby forming a container with no irregularities on the outer surface and irregularities on the inner surface with varying wall thicknesses in the circumferential direction. With this configuration, a container with no irregularities on the outer surface and irregularities on the inner surface with varying wall thicknesses in the circumferential direction can be easily manufactured.

[0015] Furthermore, the method for manufacturing this container is characterized in that, in step A, when the resin forming the parison is extruded from the die, the core or die moves up and down, causing parisons of different wall thicknesses to be extruded continuously. With this configuration, the continuous up and down movement of the core or die changes the clearance between the core and the die, and thus changes the amount of resin extruded.

[0016] As a result, the thickness of the extruded parison varies in the height direction. By sandwiching this parison between molds and inflating it from the inside with air or the like, it becomes possible to create irregularities on the inner surface of the container. The irregularities formed by this manufacturing method are formed in the height direction, resulting in an irregularity where recessed areas (sunken parts) and raised areas (elevated parts) are smoothly continuous.

[0017] Furthermore, the method for manufacturing this container is characterized in that step A involves moving the core or die up and down at predetermined intervals and with predetermined amplitude. With this configuration, containers of predetermined wall thickness can be manufactured at predetermined intervals.

[0018] Furthermore, the method for manufacturing this container is characterized in that step A involves moving a core or die up and down so that continuous irregularities are formed along the entire length of the inner surface of the container in the height direction. With this configuration, a container can be made in which continuous irregularities are formed along the entire length of the inner surface of the container in the height direction.

[0019] Furthermore, the method for manufacturing this container is characterized in that the formed container is made with different wall thicknesses in the circumferential direction. With this configuration, it is possible to create a container in which there are parts of the circumferential wall with different wall thicknesses in the circumferential direction.

[0020] Furthermore, the manufacturing method of this container is characterized in that the formed container is made with different wall thicknesses in the height direction. With this configuration, it is possible to create a container in which there are parts of the peripheral wall with different wall thicknesses in the height direction.

[0021] Furthermore, the method for manufacturing this container is characterized in that step A includes a step of gripping the lower end of the parison that has been extruded from the die and is hanging down, and twisting the parison in the circumferential direction while gripping the lower end of the parison. With this configuration, a container can be made that has spiral irregularities on its inner surface.

[0022] Further, this method for manufacturing a container is characterized in that, in the step A, the core is disposed at a position eccentric from the center position of a central hole provided in the die, the parison extruded from the die is extruded such that the wall thickness of a part of the peripheral wall is formed thinner than the wall thickness of the other part of the peripheral wall, and the formed container is formed with different wall thicknesses in the circumferential direction.

[0023] According to this configuration, by arranging the core at a position eccentric from the center position of the central hole of the die, the clearance between the core and the die varies on the left and right sides, and the amount of the resin extruded therefrom varies. As a result, the wall thickness of the extruded parison differs in the circumferential direction, and in a state where the parison is sandwiched between molds, the parison is inflated from the inside with air or the like, whereby a container having a different wall thickness in the circumferential direction of the container can be formed.

[0024] An apparatus for manufacturing a container according to one aspect of the present invention is an apparatus for manufacturing a container, comprising: means A for forming a tubular parison having irregularities on an outer surface thereof; means B for sandwiching the parison between molds; and means C for inflating the parison from the inside to form a container, wherein in the means A, an opening of a die through which the resin is extruded has a shape having irregularities on an outer periphery thereof, and the parison having irregularities on the outer surface is formed by extruding the resin from the die, and the formed container is characterized in that irregularities are formed on an inner surface thereof. According to this configuration, by using this manufacturing apparatus, it is possible to manufacture a container in which irregularities are formed in the circumferential direction of the inner surface.

[0025] Further, in this container manufacturing apparatus, the opening of the die may be configured to have a shape in which concave portions and convex portions are alternately and continuously connected in the circumferential direction.

[0026] Further, in this container manufacturing apparatus, the opening of the die may be configured to be formed in a gear shape.

[0027] Further, in this container manufacturing apparatus, the opening of the die may be configured such that the concave portions and the convex portions are smoothly connected.

[0028] Furthermore, the container manufacturing apparatus may be configured to include a core inserted through the center of a through hole communicating with the opening of the die, and resin being extruded from the gap between the die opening and the core, thereby forming a tubular parison with varying wall thicknesses in the circumferential direction.

[0029] Furthermore, the container manufacturing apparatus can be configured such that the core or the die is able to move up and down, and when the resin forming the parison is extruded from the die, the core or the die moves up and down, so that parisons of different wall thicknesses are continuously extruded.

[0030] Furthermore, the container manufacturing apparatus can be configured such that the core or the die moves up and down at predetermined intervals and with predetermined amplitude.

[0031] Furthermore, the manufacturing apparatus for this container can be configured such that the formed container has different wall thicknesses in the circumferential direction.

[0032] Furthermore, the manufacturing apparatus for this container can be configured such that the formed container has different wall thicknesses in the height direction.

[0033] Furthermore, the container manufacturing apparatus may be configured such that means A has means for gripping the lower end of the parison that has been extruded from the die and is hanging down, and twisting the parison in the circumferential direction while gripping the lower end of the parison.

[0034] Furthermore, the manufacturing apparatus for this container can be configured such that the core or the die is movable in the horizontal direction.

[0035] A container according to one aspect of the present invention has an outer surface formed as a flat surface without irregularities, and an inner surface that is smoothly connected in the circumferential direction without edges. No straight sections Mountain-shaped raised area and No straight sections It is characterized by the alternating formation of valley-shaped subsidence sections, Transparent or translucentThis is a container. With this configuration, it is possible to manufacture a container that has a flat outer surface and continuous circumferential irregularities on its inner surface, which was not possible with conventional methods.

[0036] Furthermore, this container can be configured such that the raised portion and the settled portion are continuously formed along the entire circumference of the inner surface.

[0037] Furthermore, this container can be configured such that the thickness of the top of the sedimentation section is smaller than the thickness of the thickest part of the bottom of the container.

[0038] Furthermore, this container can be configured such that the thickness of the top of the raised portion is greater than the thickness of the thickest part of the bottom of the container.

[0039] Furthermore, this container can be configured such that the thickness of the top of the sedimentation section is smaller than the thickness of the thickest part of the bottom of the container, and the thickness of the top of the raised section is larger than the thickness of the thickest part of the bottom of the container.

[0040] Furthermore, this container can be configured such that the circumferential dimensions of the submerged portion are larger than the circumferential dimensions of the raised portion. For example, if the circumferential dimensions of the raised portion are made significantly smaller than the circumferential dimensions of the submerged portion, the container can be made to have a flower-like outer shape in the cross section perpendicular to the height direction.

[0041] Furthermore, this container can be configured such that the settling portion is arc-shaped in a cross-section perpendicular to the height direction.

[0042] Furthermore, this container can be configured such that the circumferential dimensions of multiple sedimentation sections are substantially the same.

[0043] Furthermore, this container can be configured such that the circumferential dimensions of the settling portion are larger than the circumferential dimensions of the settling portion, the circumferential dimensions of multiple settling portions are substantially the same, and the settling portion is arc-shaped in a cross section perpendicular to the height direction of the container. With this configuration, the cross section perpendicular to the height direction of the container can have a flower-like outer shape, resulting in a highly aesthetic design.

[0044] Furthermore, this container can be configured with continuous irregularities along its entire length in the height direction on the inner surface.

[0045] Furthermore, this container can be constructed with varying wall thicknesses in the circumferential direction.

[0046] Furthermore, this container can be configured with ridges formed on its inner surface in the vertical direction.

[0047] Furthermore, this container can be configured such that the circumferential dimensions of multiple sedimentation sections are substantially the same.

[0048] Furthermore, this container can be configured such that the circumferential irregularities on the inner surface of the container are formed in a spiral pattern. [Effects of the Invention]

[0049] The present invention can provide a container having irregularities in the circumferential direction on its inner surface. [Modes for carrying out the invention]

[0050] <Container manufacturing equipment> Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the following embodiment. Figure 1 is a schematic diagram of a container manufacturing apparatus showing the manufacturing process of a container according to the first embodiment of the present invention. Figure 2 is a cross-sectional view of the parison forming machine of the container manufacturing apparatus. Figure 3 is a cross-sectional view of the main part of the parison forming machine. Figure 4 is an X-X cross-sectional view, where (a) shows the core in place and (b) shows the core removed. Figure 5 is an explanatory diagram illustrating the movement of the core of the parison forming machine. Figure 6 is a control diagram for controlling the core.

[0051] (1. Overall structure) First, we will explain the container manufacturing equipment, followed by the container manufacturing method, and then the container itself. This manufacturing apparatus is a manufacturing apparatus 1 (hereinafter referred to as "direct blow molding apparatus 1") that can easily manufacture containers with irregularities on the inner surface by direct blow molding.

[0052] As shown in Figure 1, the direct blow molding apparatus 1 includes a parison forming machine 5 that forms a tubular parison 4, and a container forming machine 6 that expands the parison 4 into a container shape to obtain a container 2. The parison forming machine 5 pushes out the molten resin 3 to form the parison 4, and while the parison 4 is held in the container forming machine 6, it is expanded by blowing air into the inside of the parison 4, thereby forming the container. In the direct blow molding apparatus 1, the container forming machine 6 is configured to be movable relative to the parison forming machine 5.

[0053] (2. Parison forming machine) As shown in Figures 1 and 2, the parison forming machine 5 heats the thermoplastic resin 3, and extrudes the molten resin 3 into a tube shape, thereby forming the parison 4. In this embodiment, polyethylene terephthalate (PET) is used as the thermoplastic resin 3, but other thermoplastic resins can also be used.

[0054] The parison forming machine 5 includes a die head body 8 for extruding molten thermoplastic resin into a tubular shape to form a parison 4, and a resin material supply unit 7 for supplying molten resin 3 to the die head body 8.

[0055] The resin material supply unit 7 includes a funnel-shaped resin material inlet 11, a cylindrical heating cylinder 12 installed below the resin material inlet 11 for heating the resin material, an extrusion screw 13 for pushing out the resin material inside the heating cylinder 12, and an electric motor 14 for driving the extrusion screw 13.

[0056] The extrusion screw 13 is cylindrical in shape and has helical teeth on its outer circumference, and is installed coaxially with the heating cylinder 12 inside the heating cylinder 12. The extrusion screw 13 is driven by an electric motor 14 and rotates. As a result, the resin 3 inside the heating cylinder 12 is extruded into the die head body 8.

[0057] (3. Die head) As shown in Figures 2 and 3, the die head body 8 has a mandrel 18 fitted inside it, which serves as the shaft for extruding the molten thermoplastic resin into a tube shape. An annular passage 19 is formed between the inner surface of the die head body 8 and the outer surface of the mandrel 18.

[0058] Furthermore, an annular die 20 is positioned at the end of the die head body 8, and a core 30 is positioned which is inserted through the center of an insertion hole 21 that communicates with the opening 20A of the die 20, with its tip being flush with or protruding from the die 20.

[0059] Furthermore, as shown in Figures 4(a) and 4(b), the opening 20A of the die 20 has an irregular shape on its outer circumference. The convex portions (raised portions) 20a and concave portions (sunken portions) 20b are alternately and evenly connected in a continuous and smooth manner in the circumferential direction, forming a gear-like shape. The convex portions 20a are all the same shape. In this embodiment, as an example, the die 20 has eight convex portions 20a formed at equal intervals in the circumferential direction of the die 20, but the number of convex portions 20a is not limited to eight.

[0060] Since the opening 20A of the die 20 through which the resin is extruded has a shape with a convex portion 20a and a concave portion 20b on its outer circumference, the resin 3 is extruded from the gap between the core 30 and the die 20 (see hatched area in Figure 4(a)), forming a parison 4 with a convex portion 401 and a concave portion 402 on its outer surface (see Figure 9(a)). The thickness of the parison 4 is relatively thicker at this convex portion 401.

[0061] The axis of the die head body 8 and the axis of the core 30 are aligned on the same line. The core 30 is connected to one end of the core shaft 15 through which the mandrel 18 is inserted, and the other end of the core shaft 15 is connected to the end of the die head body 8 opposite to the opening 20A and connected to the servo motor 16, so that the core 30 can move up and down.

[0062] Furthermore, this servo motor 16 is connected to a control unit (not shown), and by controlling the servo motor 16, the core 30 is controlled to move up and down.

[0063] As shown in Figures 3 and 4, a ventilation passage 34 is formed in the center of the core 30, extending axially from the ventilation opening 32. This ventilation passage 34 will be described later.

[0064] Furthermore, an annular resin path, which continues to the annular passage 19, is formed between the inner surface of the die head body 8 and the outer surface of the core 30.

[0065] The die 20 is positioned at the end of the die head body 8, and an annular resin path is formed between the inner surface of the die 20 and the outer surface of the core 30. At the opening 20A of the die 20, the die 20 and the core 30 form an annular parison discharge nozzle 33 (see Figure 4(a)). As a result, the resin fed from the extruder passes through the resin path and the parison 4 is discharged from the nozzle 33.

[0066] In this embodiment, the die 20 has a tapered surface on its inner circumferential surface near the opening 20A. 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, thereby altering the amount of resin extruded and the thickness of the parison (see Figure 5).

[0067] In this embodiment, the core 30 has a circular bottom, but it is not limited to this and can also have a gear shape, a star shape, or other shapes. Furthermore, the die 20 may be configured to move not only vertically but also horizontally. This allows for adjustment of the gap between the hole on the bottom surface of the die 20 and the bottom surface of the core 30, making it possible to adjust the thickness of the parison in the circumferential direction. This makes it possible to manufacture containers with different wall thicknesses in the circumferential direction (see Figure 12).

[0068] Furthermore, the parison forming machine 5 has a ventilation passage 22 formed in the mandrel 18 (described later) and a gas supply source 17 that supplies pressurized cooling gas to the ventilation passage 22.

[0069] The gas supply source 17 supplies pressurized cooling gas as a gas flow to the ventilation passage 22 of the mandrel 18. The ventilation passage 22 leads to the inside of the parison 4. The pressurized cooling gas is, for example, room temperature air at a predetermined pressure.

[0070] This allows pressurized cooling gas to be blown into the parison 4 through the ventilation passage 22 and the ventilation opening 32. As a result, the parison 4 formed by the die head body 8 can be kept in a tubular shape.

[0071] (4. Container forming machine) Next, a container forming machine 6 that shapes the tubular parison 4 into a container will be described. As shown in Figure 1, the container forming machine 6 comprises a base 60, two container molds 25 installed on the base 60, a driving device 27 having blow pins 26 corresponding to the diameter of the opening of the container 2 to be formed, 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 parison 4 and inflate it by blowing air or the like from inside the parison 4 to form the container shape.

[0072] Specifically, a portion of the parison 4 is housed in a container mold 25, and the parison 4 housed in the container mold 25 is cooled by injecting high-pressure air from a blow pin 26 to expand the parison 4 from the inside into the shape of a container, thereby obtaining the container 2.

[0073] The blow pin 26 may be positioned to pass through the center of the core 30 and the mandrel 18. In this case, the blow pin may be configured to move up and down, and the pressurized cooling gas may be blown out by inserting it from above the parison 4, which is sandwiched between the container-shaped components. Alternatively, the pressurized cooling gas can be blown out from above the parison 4 through the ventilation passage 22 and the ventilation port 32 of the core 30 without using a blow pin.

[0074] The container type 25 has a recessed inner surface that forms part of the container 2, and this recess is shaped to match the outer surface of the container 2. The container type 25 is also composed of a pair of detachable types 29 that are relatively movable in the lateral direction. In this embodiment, the detachable types 29 are composed of a pair, left and right, but they may be configured as, for example, three or four.

[0075] After the container mold 25 moves to the underside of the die head body 8, the parison 4 is positioned between the pair of separation molds 29. The pair of separation molds 29, which were previously separated from each other, then move closer together, and their dividing surfaces come into contact with each other. In this state, the parison 4 is expanded within the container mold 25 to form the container shape.

[0076] Furthermore, the container forming machine 6 has a ventilation passage formed in the blow pin 26 and a second gas supply source 28 that supplies pressurized cooling gas to this ventilation passage.

[0077] The second gas supply source 28 supplies room temperature air at a predetermined pressure, which serves as pressurized cooling gas, to the air passage of the blow pin 26. This air passage can communicate with the inside of the parison 4 located within the container type 25. This allows the pressurized cooling gas to be blown into the parison 4 through the air passage at the required timing.

[0078] When the formation of the container 2 by the container mold 25 is complete, the moving mechanism of the container forming machine 6 retracts the container mold 25 from the underside of the die head body 8 and moves the next container mold 25 to the underside of the die head body 8. This configuration allows for the continuous formation of containers 2.

[0079] <Container manufacturing method> (1. Overall) Next, the method for manufacturing the container (hereinafter referred to as the direct blow molding method) will be described. The direct blow molding method of this embodiment mainly comprises (1) a parison forming step in which a molten thermoplastic resin 3 is extruded into a tube shape to form a parison 4, and (2) a container forming step in which the formed parison 4 is sandwiched between container molds 25, and pressurized cooling gas is blown into the parison 4 inside the container molds 25 to expand the parison 4 into a container shape while cooling it, thereby obtaining a container 2.

[0080] (2. Parison formation process) As shown in Figure 1, in the parison formation process, solid resin 3 is introduced into the heating cylinder 12 from the resin material inlet 11. The resin 3 introduced into the heating cylinder 12 is heated by 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 by the extrusion force of the extrusion screw 13 driven by the electric motor 14.

[0081] The molten resin 3 that reaches the die head body 8 passes through the annular passage 19 and is pushed out downwards from below the die head body 8, through the gap between the die 20 and the core 30. This forms a tubular parison 4.

[0082] Furthermore, by configuring the core 30 to allow control of its vertical movement, a mechanism for adjusting the wall thickness in the height direction of the container may be provided. When the resin forming the parison 4 is extruded from the die 20, the servo motor 16 controls the reciprocating movement of the core 30 up and down, thereby changing the gap between the die 20 and the core 30 as needed, and also changing the amount of resin extruded. This makes it possible to extrude a parison 4 with alternating thick and thin wall thicknesses in the height direction (see Figures 5 and 6).

[0083] Furthermore, when this parison 4 is formed, pressurized cooling gas is blown out from the ventilation passage 22 through the ventilation opening 32. This pressurized cooling gas is weakly pressurized (for example, 0.5 to 1.0 kg / cm²). 2 The pressure is lower than that of the pressurized cooling gas blown in from the inside of the parison 4 while it is sandwiched between the container-type 25. This is to prevent the shape of the cylindrical parison 4 from substantially changing when the pressurized cooling gas in the ventilation passage 22 is blown out toward the cavity inside the softened cylindrical parison 4.

[0084] (3. Container forming process) Next, as shown in Figure 1, during the container forming process, a pair of separation molds 29 are positioned on the outside of the parison 4 in an open state. At this time, the parison 4 is hanging down from the die. Subsequently, the pair of separation molds 29 clamp the parison 4, sealing the lower side of the parison 4. During this clamping process, the lower end portion of the parison 4 is cut off.

[0085] Next, the upper end of the parison 4, whose lower end is sealed, is cut with a hot cutter (not shown).

[0086] Furthermore, the pressurized cooling gas from the ventilation passage 22 is blown out from the time the parison 4 starts to form until a predetermined portion of the parison 4 is cut. The pressurized cooling gas may also be blown out at the required timing.

[0087] Next, the blow pin 26 of the driving device 27 is inserted into the opening at the upper end of the cut parison 4. Then, pressurized air at approximately 0.39 to 0.49 MPa is blown into the parison 4, whose bottom is closed, from the outlet of the air passage of the blow pin 26. As a result, the parison 4, which is in a semi-solid state at a high temperature, expands. Consequently, the thickness of the parison 4 decreases as it expands, and the parison 4 is formed to conform to the inner surface of the container mold 25.

[0088] At this time, since thick and thin sections alternate in the circumferential direction, when parison 4 expands, the outside becomes a smooth shape that conforms to the container shape, while the thicker sections have convex portions 401 and concave portions 402 that protrude inward. As a result, a container is formed in a semi-solid state with alternating, smooth convex portions (protruding sections) 201 and non-protruding concave portions (sinking sections) 202, where the thicker and thinner sections are located. (See Figure 7)

[0089] Next, the container mold 25 is cooled, causing the container 2 to solidify. Then, the pair of separation molds 29 are separated from each other, and the container 2 is removed from the pair of separation molds 29, completing the container 2 shown in Figure 7.

[0090] Furthermore, the pressurized cooling gas passing through the ventilation passages 22 and 34 is not limited to air; it may also be a gas that does not react with the resin 3 forming the parison 4, such as an inert gas.

[0091] <Container> Figure 7(b) is a cross-sectional view of the container of this embodiment. The container 2 is a substantially cylindrical shape with a bottom, and the central part in the height direction is slightly bulging compared to the upper and lower parts. A mouth is formed at the top of the container 2, and male threads are formed on the outer surface of the mouth. The container 2 has a clean outer shape, with an inwardly raised convex portion 201 and a non-raised recessed portion 202 that are continuous in the circumferential direction, while the outside is formed as a flat surface without irregularities.

[0092] The container 2, constructed in this manner, has a flat outer surface without any irregularities, making it easy to affix labels to its outer surface. Furthermore, by making the container 2 transparent or translucent, the raised convex portion 201 and the non-raised recessed portion 202 are continuous in the circumferential direction, resulting in a very beautiful and attractive appearance when viewed from the outside due to light reflection and refraction. In addition, since the liquid inside can be seen from the outside, it is suitable as a container for storing cosmetics, pharmaceuticals, and other similar products.

[0093] Furthermore, the amount of the inwardly raised protrusion 201 can be changed by the shape of the opening 20A of the core 30 and die 20, as well as by controlling the vertical movement of the core 30 as described above. In other words, by lowering the core 30 slightly, the gap between the core 30 and die 20 widens, making it possible to increase the amount of resin extruded.

[0094] Furthermore, as shown in Figure 8, when the resin forming the parison 4 is extruded from the die 20, the core 30 is moved up and down by the control of the servo motor 16, thereby creating a container in which a continuous convex portion 203 and concave portion 204 are formed on the inner surface of the container 2 in the height direction.

[0095] <Other Embodiments> In addition to the embodiments described above, the present invention can also be configured as follows, for example. Figures 9(a) and 9(b) are schematic diagrams of a container manufacturing apparatus showing the manufacturing process of a container according to a different embodiment. Figures 10 and 11 show a container according to a different embodiment. Figure 12 is an explanatory diagram illustrating the movement of the core of the parison forming machine of a container manufacturing apparatus according to a different embodiment.

[0096] (1. Manufacturing apparatus equipped with a spiral strip forming machine) As shown in Figure 9(b), the manufacturing apparatus of the above embodiment can also be configured to include a twisting mechanism for twisting the parison in order to form spiral irregularities on the inner surface.

[0097] As shown in Figure 9(b), the twisting mechanism 100 comprises a pair of arms 102 as clamping parts, an opening and closing mechanism 103, and a rotary motor 104 as a rotating part.

[0098] The pair of arms 102 are for gripping the parison 4. For example, the arms are made of aluminum, and the outer surface of the arms 102 is coated with Teflon®.

[0099] Each arm 102 has its lower end connected to an opening / closing mechanism 103. When the opening / closing mechanism 103 is driven, the upper ends of the pair of arms 102 move apart and toward each other, causing the pair of arms 102 to open and close. Each arm 102 has an upper end that is bent inward. In addition, the arms 102 have a wide shape, which makes it easier for the arms 102 to grasp the parison 4.

[0100] Then, the arm 102 of the twisting mechanism 100 grasps the lower part of the parison 4 that has been pushed out and is hanging down, and the lower part of the outer surface of the parison 4 is crushed by the force of the arm 102. By crushing the lower part of the outer surface of the parison 4 in this way, the pair of arms 102 can firmly grasp the parison 4.

[0101] Then, with the lower part of the parison 4 gripped by the pair of arms 102, the rotary motor 104 is driven at a predetermined rotational speed and by a predetermined rotational angle. This drive of the rotary motor 104 causes the pair of arms 102 to rotate around the rotation axis of the rotary motor 104, causing the parison 4 to twist in the circumferential direction. As a result, the convex portion 401 and concave portion 402 extending in the height direction on the inner surface of the parison 4 become helical.

[0102] Subsequently, by sandwiching the parison between container-shaped molds and inflating and cooling the parison from the inside with pressurized air, a container with a spiral-shaped surface can be created.

[0103] With the addition of this twisting mechanism 100 to the manufacturing apparatus, as shown in Figures 10 and 11, it becomes possible to manufacture a container having a continuous series of convex portions 201 and concave portions 202 that are raised in the height direction on the inner surface, and a container having a spiral convex portion 201 and concave portion 202 on the inner surface.

[0104] (2. Manufacturing equipment in which the die and core can move relative to each other in the horizontal direction) Furthermore, as shown in Figure 12, the die 20 and core 30 can be configured to be movable horizontally, thereby providing a manufacturing apparatus with a mechanism for adjusting the circumferential wall thickness. In this case, only the core 30 may be configured to be horizontally movable, or the rod 50 portion including the die 20 may be configured to be horizontally movable, or the entire mandrel 18 including the core 30 may be configured to be horizontally movable. In other words, the die 20 and core 30 should be able to move horizontally relative to each other. For horizontal movement, a servo motor or the like can be connected to control the movement.

[0105] This allows the core 30 to move vertically and horizontally relative to the die 20, enabling the adjustment of the wall thickness of the extruded parison to create a container with a continuous series of convex and concave sections on the inner surface in the height direction, and a thinner wall in a portion of the circumferential direction. In addition, it is possible to create a shape in which the convex and concave sections on the inner surface are continuous in the height direction, and a portion of the wall thickness is thinner in the height direction and circumferential direction than in other parts. With such a container, the liquid inside can be pushed out by pressing the thin wall portion with a finger or the like.

[0106] (3. Others) As described above, the present invention can take the embodiments described above, but the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the present invention, and equivalents can be used in place of the elements of the embodiments. In addition, many modifications can be made without departing from the basic scope of the present invention to adapt specific situations or materials to the teachings of the present invention.

[0107] For example, in the above embodiment, the core 30 is configured to move up and down, but it is also conceivable to configure the die 20 to move up and down, in which case a similar effect can be obtained by moving the die 20 up and down when extruding the parison. In this case, for example, the rod 50 can be made retractable so that the die 20 can move up and down. Therefore, the present invention is not limited to the embodiments described above, but includes all embodiments that fall within the scope of the claims. [Brief explanation of the drawing]

[0108] [Figure 1] Schematic diagram of a container manufacturing apparatus showing the manufacturing process of a container according to one embodiment of the present invention. [Figure 2] Cross-sectional view of the parison forming machine, a manufacturing device for the same container. [Figure 3] Cross-sectional view of the main part of the parison forming machine. [Figure 4] Figure 1 shows a cross-sectional view along the line X-X, where (a) shows the view with the core in place, and (b) shows the view without the core. [Figure 5] This diagram illustrates the movement of the core of the parison forming machine. [Figure 6] Control diagram for controlling the core of the parison forming machine. [Figure 7] A diagram showing a container according to the first embodiment of the present invention. [Figure 8] Diagram showing a modified form of the container. [Figure 9] Schematic diagram of a container manufacturing apparatus showing the manufacturing process of a container according to another embodiment. [Figure 10] Diagram showing a modified form of the container. [Figure 11] Diagram showing a modified form of the container. [Figure 12] Diagram illustrating the movement of the core of a parison forming machine in a container manufacturing apparatus according to another embodiment. [Explanation of Symbols]

[0109] 1. Direct blow molding apparatus 2 containers 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 tube 13. Extrusion Screw 14 Electric motor 15 Core Shaft 16 Servo motors 17. Gas supply source 18 Mandrels 19 Circular Passage 20 di 20A opening 20a Convex part (raised part) 20b Recess (sinking area) 21 Through hole 22 Ventilation duct 25 Container type 26 Blowpin 27. Driving device 28 Gas supply source 29 Separate type 30 cores 32 Ventilation hole 33 Nozzle opening 34 Ventilation duct 60 bases 100 Twisting mechanism 101 Base 102 Arm 103 Opening and closing mechanism 104 Rotation Motor 201 Convex part of the container 202 Recess of the container 203 Convex part of the container 204 Recess of the container 401 Convex part on the outer edge of the parison 402 Recess on the outer perimeter of the parison

Claims

1. The outer surface is formed as a flat surface without irregularities, and On the inner surface, along the entire circumference, alternating and continuous sections are formed: mountain-shaped raised sections without edges and straight lines, and valley-shaped recessed sections without straight lines, with smooth, continuous connections. A transparent or translucent container characterized in that, in a cross-section perpendicular to the height direction of the container, the settling portion is arc-shaped.

2. The container according to claim 1, wherein in a cross-section perpendicular to the height direction of the container, the circumferential arc length of the settled portion is greater than the circumferential arc length of the raised portion.

3. The container according to claim 1, wherein the circumferential arc lengths of the multiple sedimentation sections are equal to each other.

4. The container according to any one of claims 1 to 3, wherein relatively thick and thin portions are alternately formed in the height direction of the inner surface.

5. A container according to any one of claims 1 to 3, which is formed with different wall thicknesses in the circumferential direction.

6. A container according to any one of claims 1 to 3, which is formed with different wall thicknesses in the height direction.

7. The container according to any one of claims 1 to 3, wherein the raised portion and the settled portion are continuous on the inner surface in the height direction.

8. The container according to claim 7, wherein the raised portion and the settled portion are formed in a spiral shape.

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