Preform, injection molding mold, temperature adjustment mold, method for manufacturing resin container, and apparatus for manufacturing resin

Abstract

A preform (20) produced by an injection molding unit (110) of a hot parison type blow molding device and blow-molded into a resin container by a blow molding unit (130), the preform (20) being provided with: a neck part (21) for forming an opening of the preform (20); a trunk section (22) connected to the neck section (21); and a bottom section (23) connected to the body section (22) and closing one end of the preform (20), the body section (22) being provided with a connection section (22a) connected to the neck section (21) and a thin body section (22b) formed so as to have a smaller diameter than the neck section (21), and the neck section (21) and the connection section (22a) and the connection section (22a) and the thin body section (22b) being connected in an L-shape to form a stepped section (22c).

Description

Technical Field

[0001] The present disclosure relates to a preform, an injection molding die, a temperature-regulating die, a method for manufacturing a resin container, and an apparatus for manufacturing a resin container. Background Art

[0002] Patent Document 1 discloses a preform for producing a resin container.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Publication No. 04-034925 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The shape of the preform needs to be appropriately selected or designed according to the shape of the resin container. If the preform shape is inappropriate, molding defects such as poor wall thickness distribution at a predetermined portion of the resin container are likely to occur during the molding process.

[0008] An object of the present disclosure is to provide a preform, an injection molding die, a temperature-regulating die, a method for manufacturing a resin container, and an apparatus for manufacturing a resin container, which suppress the occurrence of molding defects.

[0009] Solutions for solving problems

[0010] A preform according to one aspect of the present disclosure is manufactured by an injection molding section of a hot parison blow molding apparatus and blow-molded into a resin container by the blow molding section. The preform includes:

[0011] a neck portion forming an opening of the preform;

[0012] a torso connected to the neck; and

[0013] The bottom portion is connected to the trunk portion to close one end of the preform.

[0014] The trunk portion includes a connection portion connected to the neck portion and a thin trunk portion having a diameter smaller than that of the neck portion.

[0015] The neck portion and the connecting portion, as well as the connecting portion and the slender body portion, are connected in an L-shape to form a step portion.

[0016] An injection molding die according to one aspect of the present disclosure is used to manufacture a preform by an injection molding portion of a hot parison blow molding device, wherein:

[0017] The injection molding die comprises an injection cavity comprising a neck forming portion, a body forming portion, and a bottom forming portion. The neck forming portion forms a neck portion of the preform, the body forming portion forms a body portion connected to the neck, and the bottom forming portion forms a bottom portion connected to the body portion to close one end portion of the preform.

[0018] The trunk forming portion includes a connection forming portion connected to the neck forming portion and a thin trunk forming portion formed to be narrower than the neck forming portion.

[0019] The neck forming portion and the connection forming portion, as well as the connection forming portion and the slender body forming portion, are connected in an L-shape to form a step forming portion.

[0020] The temperature regulating mold of one aspect of the present disclosure is used to regulate the temperature of the above-mentioned preform to a temperature suitable for blow molding, wherein:

[0021] The temperature regulating mold has:

[0022] a heater arranged to cover at least the connecting portion; and

[0023] The cooling unit is provided at a bottom side relative to the heater.

[0024] A method for manufacturing a resin container according to one aspect of the present disclosure manufactures a resin container by hot parison blow molding the preform described above, the method comprising:

[0025] Injection molding process, injecting molten resin into an injection cavity formed by an injection molding die to form the preform;

[0026] a temperature adjustment step of adjusting the temperature of the preform to a temperature suitable for blow molding; and

[0027] The blow molding step is to blow-mold the temperature-controlled preform.

[0028] A resin container manufacturing apparatus according to one aspect of the present disclosure manufactures a resin container by hot parison blow molding the preform, the resin container manufacturing apparatus comprising:

[0029] An injection molding unit injects molten resin into the injection cavity formed by the injection molding die to form the preform;

[0030] a temperature regulating unit including a temperature regulating mold for regulating the temperature of the preform to a temperature suitable for blow molding; and

[0031] The blow molding section blow-moldes the temperature-controlled preform.

[0032] Effects of the Invention

[0033] According to the present disclosure, it is possible to provide a preform, an injection molding die, a temperature-regulating die, a method for manufacturing a resin container, and an apparatus for manufacturing a resin container, in which the occurrence of molding defects is suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a block diagram of the manufacturing apparatus of the resin container according to the present embodiment.

[0035] Figure 2 This is a perspective view of the preform according to this embodiment.

[0036] Figure 3 It is a perspective view of the resin container according to this embodiment.

[0037] Figure 4 This is a diagram showing an example of an injection molding portion.

[0038] Figure 5 This is a diagram showing an example of a temperature adjustment unit.

[0039] Figure 6 This is a diagram showing an example of a blow molding section.

[0040] Figure 7 This is a diagram illustrating a method for manufacturing a resin container. DETAILED DESCRIPTION

[0041] Hereinafter, as one embodiment of the present disclosure, a resin container manufacturing apparatus 100 and a manufacturing method will be described with reference to the drawings. For convenience of description, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component.

[0042] For convenience of explanation, reference will be made to the "upper and lower directions" as appropriate. Here, the "upper and lower directions" encompass both "upward" and "downward." Reference symbol U in the following figures indicates the upward direction. Reference symbol D indicates the downward direction. Unless otherwise specified, the description will be based on the direction in which the openings of the preform and resin container are located as the upward direction.

[0043] Figure 1 The resin container 30 of this embodiment (see Figure 3 ) is a block diagram of a manufacturing apparatus 100. The manufacturing apparatus 100 is configured to form a preform 20 (see Figure 2 ) The resin container 30 is manufactured by hot parison blow molding. Figure 1As shown in the example, the manufacturing apparatus 100 includes an injection molding unit 110, a temperature control unit 120, a blow molding unit 130, and a take-out unit 140. The injection molding unit 110 manufactures a preform 20, described later, by injecting molten resin from an injection device 111. The temperature control unit 120 controls the temperature of the preform 20 to a temperature suitable for blow molding. The blow molding unit 130 manufactures a resin container 30 by blow molding the preform 20. The take-out unit 140 removes the resin container 30 manufactured by the blow molding unit 130.

[0044] The material constituting the preform 20 or the resin container 30 is a thermoplastic synthetic resin. For example, it can be selected from PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (polycyclohexanedimethylene terephthalate), Tritan (a registered trademark of Eastman Chemical Company), PP (polypropylene), PE (polyethylene), PC (polycarbonate), PES (polyethersulfone), PPSU (polyphenylsulfone), PS (polystyrene), COP / COC (cyclic olefin polymer), PMMA (polymethyl methacrylate: acrylic), PLA (polylactic acid), and the like. It should be noted that the most preferred material for the preform 20 and the resin container 30 in this embodiment is PET.

[0045] The injection molding unit 110, the temperature regulating unit 120, the blow molding unit 130, and the take-out unit 140 are arranged at positions after being rotated by a predetermined angle with the conveying unit 150 as the center. In this embodiment, the predetermined angle is 90 degrees. The conveying unit 150 has a rotating plate (not shown). The rotating plate is equipped with a neck mold 151 (see Figure 4 The preform 20 is held by the neck mold 151 and rotated by the rotating plate to transport the preform 20 to each of the injection molding section 110, the temperature control section 120, the blow molding section 130, and the removal section 140. It should be noted that the resin container 30 may be transported only between the blow molding section 130 and the removal section 140.

[0046] Figure 2 : is a perspective view of the preform 20 of this embodiment. Figure 2 As shown in the example, the preform 20 includes a neck portion 21, a body portion 22, and a bottom portion 23. The neck portion 21 forms the opening of the resin container. The body portion 22 is connected to the neck portion 21. The body portion 22 forms the side of the resin container through blow molding. The bottom portion 23 is connected to the body portion 22. The bottom portion 23 closes one end of the preform 20 and forms the bottom surface of the resin container 30 through blow molding.

[0047] The body portion 22 includes a connecting portion 22a connected to the neck portion 21 and a thin body portion 22b having a diameter smaller than that of the neck portion 21. The lower portion of the neck portion 21 and the connecting portion 22a, as well as the connecting portion 22a and the upper portion of the thin body portion 22b, are connected in an L-shape to form a step portion (recess) 22c. Ideally, the angle (angle) θ formed by the central axis X of the preform 20 and the extension line of the outer surface of the connecting portion 22a is 70° to 90°, more preferably 80° to 89° (see Figure 4 ). In addition, it is desirable that the angle (angle) θ' formed by the line of the outer surface of the connecting portion 22a of the preform 20 (the line of the lower surface) and the line of the outer surface of the narrow body portion 22b (the line of the side) is 90° to 110°, more preferably 91° to 100° (refer to Figure 4 ).

[0048] Figure 3 This is a perspective view of a resin container 30. The resin container 30 includes a container head 31, a container shoulder 32, a container body 33, and a container bottom 34. The container head 31 is formed by the neck 21 of the preform 20 and forms the opening of the resin container 30. The container shoulder 32 is formed by a portion of the body 22 of the preform 20 (a portion on the neck 21 side of the body 22) and is connected to the container head 31. The container body 33 is formed by a portion of the body 22 of the preform 20 (a portion on the bottom 23 side of the body 22) and is connected to the container shoulder 32. The container bottom 34 is formed by the bottom 23 of the preform 20 and is connected to the container body 33. The container shoulder 32 is formed so that its diameter increases as it approaches the container bottom 34.

[0049] Figure 4The injection molding section 110 is shown as an example. The injection molding section 110 includes an injection molding mold 112. The injection molding mold 112 constitutes an injection cavity (molding space). The injection molding mold 112 includes an injection molding core 113 and an injection cavity mold 114. In addition, the injection molding mold 112 may also include a neck mold 151 that also serves as a part of the conveying unit 150 (temporarily) during molding. The injection molding core 113 mainly defines an injection cavity corresponding to the inner wall surface of the preform 20. The injection cavity mold 114, together with the neck mold 151, defines an injection cavity corresponding to the outer wall surface of the preform 20. Specifically, the neck mold 151 defines an injection cavity corresponding to the outer wall surface of the neck 21 of the preform 20, and the injection cavity mold 114 defines an injection cavity corresponding to the outer wall surface of the body 22 of the preform 20. The neck mold 151 is an example of a neck forming portion. The injection cavity mold 114 is an example of a body forming portion and a bottom forming portion. The injection cavity mold 114, which serves as a trunk forming portion, includes a connection forming portion 114a and a thin trunk forming portion 114b. The thin trunk forming portion 114b is formed to be narrower (smaller in diameter) than the injection cavity surface width of the neck mold 151. The neck mold 151 and the connection forming portion 114a, as well as the connection forming portion 114a and the thin trunk forming portion 114b, are connected in an L-shape (approximately at a right angle) to form a step forming portion. Ideally, the line representing the outer shape of the neck mold 151, the connection forming portion 114a, and the thin trunk forming portion 114b is crank-shaped. The angle (angle) formed by the connection forming portion 114a and the central axis X of the preform 20 is 70° to 90°, more preferably 80° to 89°. Furthermore, the angle formed by the outer shape line of the connection portion forming portion 114 a and the outer shape line of the slender body portion forming portion 114 b is preferably 90° to 110°, more preferably 91° to 100°.

[0050] like Figure 4 As shown in the example, the preform 20 also has characteristics related to the wall thickness distribution and shape. The thickness of the approximately vertical wall portion (excluding the threaded portion) constituting the neck 21 is set to T1, the thickness of the approximately horizontal wall portion constituting the connecting portion 22a is set to T2, and the thickness of the approximately conical wall portion constituting the thin body portion 22b is set to T3. At this time, at least the relationship (condition) of T2>T1 holds true, and furthermore, the relationship of T3≥T2>T1 may also hold true. Moreover, on the inner surface of the preform 20, the radius of curvature of the curved portion connecting the neck 21 and the connecting portion 22a is set to R1, and the radius of curvature of the curved portion connecting the connecting portion 22a and the thin body portion 22b is set to R2. At this time, the relationship R2>R1 holds true. Moreover, it is preferred that the diameter of the inner wall surface 131c of the blow molding cavity (the diameter of the container body portion 33, refer to Figure 6) is set to 2 to 4 times or less, preferably 2.6 to 3.7 times or less, of the diameter of the thin trunk portion 22b (preferably, the transverse axis stretching ratio of the thin trunk portion 22b of the preform 20 is set to 2 to 4 times, preferably 2.6 to 3.7 times). In addition, as Figure 6 As shown in the example, let D2 be the radial length of the connecting portion 22a, D3 be the radial length from the outer surface of the narrow body portion 22b to the body forming portion 131e (container body portion 33), and D4 be the radial length from the outer diameter end surface of the connecting portion 22a (or the neck portion 21) to the shoulder forming portion 131d (the diameter of the container shoulder). In this case, the relationship D3 > D2 and D4 > D2 holds. Furthermore, it is preferable that the lower end position of the connecting portion 22a be set higher than the lower end position P of the shoulder forming portion 131d (container shoulder portion 32) and the upper end position of the body forming portion 131e (container body portion 22).

[0051] Figure 5 The temperature regulating part 120 is shown as an example. The temperature regulating part 120 includes a temperature regulating mold member. The temperature regulating mold member includes a temperature regulating mold (temperature regulating kettle mold) 121, a cooling rod (hollow rod member, temperature regulating rod) 122 and a fitting core 123. In addition, the temperature regulating mold member may also include a neck mold 151 which is also a part of the conveying unit 150 during molding (temporarily). The inner wall surface of the temperature regulating mold 121 constitutes a temperature regulating cavity (molding space). The temperature regulating cavity corresponds to the shape of the outer wall surface of the preform 20. The cooling rod 122 is configured to be displaceable in the up and down directions. A first air vent 122a is formed at the top end of the cooling rod 122. The first air vent 122a is configured to introduce (supply) or extract (exhaust) compressed air through the interior of the cooling rod 122. A second air vent 122b is formed between the outer surface of the cooling rod 122 and the inner surface of the fitting core 123. The second air vent 122b is also configured to introduce (supply) or guide (exhaust) compressed air.

[0052] The temperature regulating mold 121 includes a heater (heating portion) 121a and a cooling portion 121b. The heater 121a is provided to cover at least the connecting portion 22a. The cooling portion 121b is provided at a position closer to the bottom 23 than the heater 121a. Alternatively, the heater 121a may be, for example, a ring heater 121a1, which is arranged at the upper portion of the temperature regulating mold 121 (the portion including the connecting portion 22a and corresponding to the step portion 22c). The heater 121a heats the step forming portion (at least the connecting portion 22a and its adjacent portion) of the preform 20 by radiant heat (radiant heat) generated by infrared rays and heat transfer achieved by contact with the mold surface. In addition, a heater 121a such as a belt heater 121a2 may also be provided at the lower portion of the temperature regulating mold 121 (the portion corresponding to the bottom 23). The cooling section 121b may be configured to allow a temperature regulating medium or a cooling medium to flow through a flow path formed inside the temperature regulating mold 121. In addition, the heater (heating section) 121a is set to a temperature higher than that of the cooling section 121b.

[0053] Figure 6 The blow molding section 130 is shown as an example. The blow molding section 130 includes at least a blow molding mold 131, an extension rod 132, and a blow core 133 that supplies and discharges blowing air (second compressed air) as a blow molding mold component. In addition, the blow molding mold component may also include a neck mold 151 that also serves as a part of the conveying unit 150 (temporarily) during molding. The blow molding mold 131 is composed of a pair of blow cavity parting molds 131a and a bottom mold 131b, and is configured to define the shape of the resin container 30 (the inner wall surface 131c of the blow cavity). The blow cavity parting mold 131a includes a shoulder forming portion 131d that defines the container shoulder 32 and a body forming portion 131e that defines the container body 33. The extension rod 132 is configured to be displaceable in the up and down directions. The extension rod 132 is arranged to contact the inner surface of the bottom 23 of the preform 20 conveyed to the blow molding unit 130, thereby extending the preform 20 downward. The blow core 133 abuts the neck 21 of the preform 20 in an airtight manner, supplies blow air to the preform 20, and exhausts the blow air from the molded resin container 30.

[0054] Next, a method for producing a resin container will be described. Figure 7 The following is an example of a method for manufacturing a resin container. Figure 7 As shown in the example, the method for manufacturing a resin container includes an injection molding step S1, a temperature adjustment step S2, and a blow molding step S3. The manufacturing method of this embodiment further includes a container removal step S4.

[0055] like Figure 4As shown in the example, the injection molding step S1 includes injecting molten resin into the injection cavity formed by the injection mold 112 to form the preform 20. The molten resin injected into the injection cavity by the injection device 111 is cooled by the injection mold 112, thereby forming the preform 20. Here, the connection-forming portion 114a forms the inner wall surface of the injection cavity corresponding to the connection portion 22a, and the slender portion forming portion 114b forms the inner wall surface of the injection cavity corresponding to the slender portion 22b. The neck mold 151, which serves as the neck-forming portion, is connected to the connection-forming portion 114a, and the connection-forming portion 114a and the slender portion forming portion 114b in an L-shape. Therefore, the neck 21 and the connection portion 22a, and the connection portion 22a and the slender portion 22b of the preform 20 are also connected in an L-shape. Therefore, the lines representing the outer shapes of the neck 21, the connection portion 22a, and the slender portion 22b of the preform 20 form a crank shape. In the injection molding process S1, the preform 20 may be demolded from the injection molding mold 112 at a high temperature. Specifically, when the preform 20 is injection molded, in the cooling process after the filling process (including the pressure holding process) is completed, the cooling time is set to less than 1 / 2 of the filling time, preferably less than 1 / 3, and more preferably 0 seconds, so that the preform 20 is demolded from the injection molding mold 112 in a state where the latent heat is high. The preform 20 after being demolded from the injection molding mold 112 is conveyed to the temperature regulating unit 120 while being maintained in the neck mold 151. It should be noted that the size relationship of the gaps (spaces) at various parts of the injection cavity is the same as the size relationship of the thicknesses of various parts of the preform 20.

[0056] like Figure 5 As shown in the example, the temperature adjustment step S2 includes adjusting the temperature of the preform 20 to a temperature suitable for blow molding. Specifically, the preform 20 conveyed from the injection molding section 110 to the temperature adjustment section 120 contacts the temperature adjustment mold 121, thereby being temperature-adjusted to a temperature suitable for blow molding. In the temperature adjustment step S2, it is ideal that at least the connecting portion 22a is heated. The heater 121a heats at least the connecting portion 22a, and the cooling section 121b cools at least the slender body portion 22b separated from the connecting portion 22a. The heater 121a can locally suppress the heat loss (temperature drop) of the connecting portion 22a caused by the compressed air, and as needed, the heat (temperature) of the connecting portion 22a can also be locally increased compared to the injection molding demolding. The bottom 23 can be cooled by providing the cooling section 121b in a manner covering the bottom 23, or it can be heated by providing a heater near the bottom 23.

[0057] Furthermore, the temperature control step S2 of this embodiment includes the following steps: after forming the preform 20, compressed air is introduced into the interior of the preform 20 through the first air vent 122a. The exterior (outer surface) of the preform 20 comes into contact with the temperature control cavity (inner wall surface of the temperature control mold 121) of the temperature control mold 121 by introducing compressed air through the first air vent 122a provided in the cooling rod 122 inserted into the interior of the preform 20, or the second air vent 122b provided in the fitting core 123. Subsequently, compressed air is continuously introduced through the first air vent 122a or the second air vent 122b to cool the preform 20 from the interior (inner surface). The introduced compressed air is discharged through the first air vent 122a or the second air vent 122b, which is responsible for introducing the compressed air. Therefore, the exterior of the preform 20 (the preform 20 from the outside) is cooled and temperature-regulated by contact with the temperature-regulating mold 121, while the interior of the preform 20 (the preform 20 from the inside) is cooled by the continuous introduction and flow of compressed air. Thus, in the temperature-regulating step S2, the preform 20 can be cooled at a high speed. The preform 20, cooled to a temperature suitable for blow molding in the temperature-regulating section 120, is conveyed to the blow molding section 130 while being held in the neck mold 151.

[0058] like Figure 6 As shown in the example, the blow molding step S3 includes blow molding the preform 20 using the second compressed air (blowing air) to produce a resin container. In this embodiment, the blow molding step S3 also includes extending the preform 20 by displacing (lowering) the extension rod 132. The second compressed air is set to a higher pressure than the compressed air used in the temperature adjustment step S2.

[0059] Specifically, the preform 20, which has been transported from the temperature control unit 120 to the blow molding unit 130, is housed in the blow molding mold 131. Next, the inner surface of the bottom 23 contacts the extension rod 132 and is extended downward. Blowing air is then introduced into the interior of the preform 20 from the blow core 133, which abuts the neck 21, to blow-mold the preform 20. The blow molding process deforms the preform 20 into a shape corresponding to the inner wall surface 131c of the blow cavity defined by the blow molding mold 131, thereby forming a resin container 30. At this time, the distance D1 from the connecting portion 22a to the blow molding mold 131, which constitutes the inner wall surface 131c of the blow cavity, is longer than that of a preform having a body portion that gradually tapers from the neck to a specific outer diameter, as disclosed in Patent Document 1. In the temperature adjustment step S2, sufficient heat is ensured in the connection portion 22a, so the connection portion 22a is appropriately stretched and thinned, which can suppress unnecessary thickening of the container shoulder 32. The manufactured resin container is conveyed to the removal unit 140 while being held by the neck mold, and is removed from the manufacturing apparatus 100 in the container removal step S4.

[0060] Furthermore, the preform is manufactured or designed in such a way that it has the optimal shape based on the shape of the resin container to be manufactured. The preform with the optimal shape is less likely to produce poor molding during the manufacture of the resin container, which can reduce the amount of waste plastic. The optimal preform shape is often different for narrow-mouthed containers and wide-mouthed containers. For example, in the case of a narrow-mouthed container, it is preferred to have a preform shape in which the upper part of the body just below the neck is strongly contracted and the lower part of the body is slowly contracted toward the bottom. On the other hand, in the case of a wide-mouthed container, it is preferred to have a preform shape in which the body just below the neck is slowly contracted toward the bottom and the body is roughly conical. In particular, in the hot preform type (one-step) blow molding method that utilizes the heat during injection molding, the heat distribution from injection molding will vary greatly depending on the shape and wall thickness distribution of the preform, thereby significantly affecting the elongation during blow molding. Therefore, the design of the preform shape is very important. However, in the production of resin containers having a mouth diameter close to a predetermined value (for example, a mouth diameter intermediate between a wide-mouth container and a narrow-mouth container), it is sometimes difficult to select a preform of an optimal shape.

[0061] When blow molding a preform that is not in the optimal shape to produce a resin container, molding defects are likely to occur. For example, in the case of the preform shape disclosed in Patent Document 1, the distance from the preform to the blow molding die is shortened, resulting in a low stretch ratio, which may prevent proper blow molding and cause molding defects. The body portion near the neck is particularly prone to excessive cooling due to its proximity to the neck mold and the tendency to be closer to the blow molding die. Therefore, this portion is particularly prone to molding defects (e.g., forming defects that are annular or abnormally thick compared to other parts (ring defects)).

[0062] According to the above configuration, the connecting portion 22a and the thin trunk portion 22b are arranged so as to decrease in diameter toward the central axis X of the preform 20 when viewed from the neck portion 21. As a result, the distance D1 between the connecting portion 22a and the thin trunk portion 22b and the inner wall surface of the blow cavity during blow molding is increased, thereby ensuring a high extension ratio of the connecting portion 22a and the thin trunk portion 22b, thereby suppressing the occurrence of molding defects.

[0063] Furthermore, the L-shaped bends between the neck 21 and the connecting portion 22a, and between the connecting portion 22a and the narrow body portion 22b, increase the portion of the connecting portion 22a that is isolated from the temperature-regulating mold 121 (the connecting portion 22a is not in contact with the cooling portion 121b and is therefore less likely to be cooled). This facilitates the maintenance of latent heat in the portion of the body portion 22 connected to the neck 21, namely, the connecting portion 22a. This prevents molding defects caused by insufficient latent heat in the body portion 22 near the neck 21.

[0064] In the injection molding die 112 and the resin container manufacturing apparatus 100 constructed as described above, the neck mold 151, which serves as the neck forming portion, is connected to the connection forming portion 114a, and the connection forming portion 114a and the slender body forming portion 114b, in an L-shape to form a step forming portion. Therefore, by injecting molten resin into the injection cavity formed by the step forming portion, a preform 20 can be manufactured in which the neck 21 and the connection 22a, and the connection 22a and the slender body 22b are bent in an L-shape. By blow-molding the preform 20 in this shape, which increases the elongation ratio directly below the neck, the occurrence of molding defects can be suppressed. The resin container manufacturing method is a method of manufacturing a resin container by hot-blanket blow molding the preform 20 described above. Therefore, molding defects in the resin container can be suppressed.

[0065] According to the aforementioned preform 20, the angle θ formed between the central axis X of the preform 20 and the connecting portion 22a is between 70° and 90°. Furthermore, in the aforementioned injection mold 112, the connecting portion forming portion 114a is arranged so that the angle θ formed with the central axis X of the preform 20 is between 70° and 90°. Consequently, the distance D1 between the connecting portion 22a and the narrow body portion 22b until they reach the blow cavity is further increased, thereby suppressing molding defects caused by an excessively low stretch ratio.

[0066] The temperature-controlled mold 121 of the above configuration includes a heater 121a and a cooling unit 121b. Furthermore, in the above-described method for manufacturing a resin container, at least the connecting portion 22a is heated. This ensures sufficient latent heat in the body portion 22 (connecting portion 22a) near the neck 21. This prevents molding defects caused by insufficient latent heat.

[0067] In the injection molding step S1 of this embodiment, the preform 20 is demolded from the injection mold 112 at a high temperature. In the temperature control step S2, compressed air is introduced into the interior of the preform 20. The injection molding section 110 of this embodiment is configured to demold the preform 20 from the injection mold 112 at a high temperature, and the temperature control section 120 includes a mechanism for cooling the preform 20 using compressed air or the like. To shorten the cycle time for manufacturing resin containers, it is important to shorten the injection molding step S1. In this embodiment, the preform 20 is demolded at a high temperature, thereby shortening both the injection molding step S1 and the cycle time for manufacturing resin containers. If the preform is cooled slowly in the temperature control step S2, it may cause appearance defects such as whitening. The exterior of the preform 20 is cooled by contact with the inner wall surface of the temperature control mold (temperature control kettle mold), while the interior of the preform 20 is cooled by the introduction of compressed air, thereby increasing the cooling rate of the preform 20.

[0068] While the embodiments of the present disclosure have been described above, the technical scope of the present disclosure should not be construed in a limiting sense based on the description of these embodiments. These embodiments are merely examples, and those skilled in the art will appreciate that various modifications of these embodiments are possible within the scope of the invention as described in the claims. The technical scope of the present disclosure should be determined based on the scope of the invention as described in the claims and their equivalents.

[0069] This application is based on Japanese patent application No. 2022-204380 filed on December 21, 2022, the contents of which are incorporated herein by reference.

[0070] Description of Reference Numerals

[0071] 20: preform;

[0072] 21: Neck;

[0073] 22: trunk;

[0074] 22a: connecting part;

[0075] 22b: thin trunk;

[0076] 22c: step part;

[0077] 23: bottom;

[0078] 100: Manufacturing device;

[0079] 110: injection molding department;

[0080] 111: injection molding device;

[0081] 112: Injection molding mold;

[0082] 113: injection molding core;

[0083] 114: injection cavity mold;

[0084] 114a: connection portion forming portion;

[0085] 114b: forming part of the slender trunk;

[0086] 120: temperature regulating unit;

[0087] 121: Temperature regulating mold;

[0088] 121a: heater;

[0089] 121b: cooling unit;

[0090] 122: cooling rod;

[0091] 122a: first ventilation port;

[0092] 122b: second ventilation port;

[0093] 123: Chimeric core;

[0094] 130: blow molding department;

[0095] 131: Blow molding mold;

[0096] 132: extension rod;

[0097] 140: extraction part;

[0098] 150: conveying unit;

[0099] 151: Neck mold;

[0100] D1: Distance.

Claims

1. A preform produced by an injection molding section of a hot parison blow molding apparatus and blow-molded into a resin container by a blow molding section, the preform comprising: a neck portion forming an opening of the preform; a torso connected to the neck; and The bottom portion is connected to the trunk portion to close one end of the preform. The trunk portion includes a connection portion connected to the neck portion and a thin trunk portion having a diameter smaller than that of the neck portion. The neck portion and the connecting portion, as well as the connecting portion and the slender body portion, are connected in an L-shape to form a step portion.

2. The preform according to claim 1, wherein The angle formed between the central axis of the preform and the connecting portion is 70° to 90°.

3. An injection molding die for producing a preform by an injection molding section of a hot parison blow molding device, wherein: The injection molding die comprises an injection cavity comprising a neck forming portion, a body forming portion, and a bottom forming portion. The neck forming portion forms a neck portion of the preform, the body forming portion forms a body portion connected to the neck, and the bottom forming portion forms a bottom portion connected to the body portion to close one end portion of the preform. The trunk forming portion includes a connection forming portion connected to the neck forming portion and a thin trunk forming portion formed to be narrower than the neck forming portion. The neck forming portion and the connection forming portion, as well as the connection forming portion and the slender body forming portion, are connected in an L-shape to form a step forming portion.

4. The injection molding die according to claim 3, wherein: The connection portion forming portion is disposed so as to form an angle of 70° to 90° with the central axis of the preform.

5. A temperature regulating mold for regulating the temperature of the preform according to claim 1 or 2 to a temperature suitable for blow molding, wherein: The temperature regulating mold has: a heater arranged to cover at least the connecting portion; and The cooling unit is provided at a bottom side relative to the heater.

6. A method for producing a resin container, comprising: producing the resin container by hot parison blow molding the preform according to claim 1 or 2, the method comprising: Injection molding process, injecting molten resin into an injection cavity formed by an injection molding die to form the preform; a temperature adjustment step of adjusting the temperature of the preform to a temperature suitable for blow molding; and The blow molding step is to blow-mold the temperature-controlled preform.

7. The method for manufacturing a resin container according to claim 6, wherein: In the injection molding process, the preform is demolded from the injection molding mold at a high temperature. In the temperature adjustment step, compressed air is introduced into the interior of the preform.

8. The method for manufacturing a resin container according to claim 6, wherein: In the temperature adjustment step, at least the connection portion is heated.

9. A manufacturing apparatus for a resin container, comprising: An injection molding section that injects molten resin into the injection cavity formed by the injection molding die according to claim 3 or 4 to form the preform; A temperature regulating unit, comprising a temperature regulating mold, for regulating the temperature of the preform to a temperature suitable for blow molding; as well as The blow molding section blow-moldes the temperature-controlled preform.

10. The manufacturing apparatus for a resin container according to claim 9, wherein The injection molding part is configured to demold the preform from the injection molding mold at a high temperature. The temperature regulating part includes the temperature regulating mold and a cooling rod, and the temperature regulating mold includes a temperature regulating cavity for contact with the preform. A ventilation hole is formed on the cooling rod. The cooling rod is configured to introduce compressed air from the air permeable port into the interior of the preform in contact with the inner surface of the temperature control chamber.

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