Injection stretch blow molding method and temperature adjusting rod

Abstract

The invention provides a molding method for injection stretch blow molding and a temperature control lever, which can obtain a molded article having a rich and colorful shape by partially changing the wall thickness of the side wall of the molded article. The molding method for injection stretch blow molding comprises an injection molding step, a temperature adjustment step, a stretch blow molding step, and a removal step. The injection molding step prepares a cylindrical preform from a plasticized material. In the temperature adjusting step, the temperature of the preform after the injection molding step is adjusted by a temperature adjusting rod (31); an extension blow molding step in which pressurized air is blown into the preform after the temperature adjustment step from a nozzle in a closed mold and extension blow molding is performed; and a removal step for removing the product that has been cooled and cured in the stretch blow molding step, in which an inner surface-side uneven surface (12) is formed on the inner surface side of the side wall of the molded article (11) by using a structure provided with an outer surface uneven surface (34) on the rod side surface of the temperature adjustment rod (31), thereby partially changing the wall thickness of the side wall.

Description

Technical Field

[0001] The invention relates to an injection, stretching and blow molding method and a temperature regulating rod. Background Art

[0002] The use of a hot Plesson blow molding machine for the production of molded products such as resin containers is well known. Hot Plesson blow molding machines utilize the heat retained during injection molding of preforms to blow-mold the resin container. Compared to cold Plesson blow molding, hot Plesson machines offer advantages in enabling the production of a wide variety of beautiful resin containers with excellent appearance.

[0003] Generally speaking, preforms immediately after injection molding do not have a temperature distribution suitable for container shaping. Therefore, in the hot Palisson blow molding cycle, a preform temperature adjustment step (hereinafter referred to as the temperature adjustment step) is performed between the injection molding and blow molding steps to suppress temperature deviations in the preform or to give the preform a desired temperature distribution suitable for container shaping. In this temperature adjustment step, a temperature adjustment rod that mimics the internal shape of the preform is generally inserted into the interior of the preform, and the inner circumference of the preform is brought into close contact with the temperature adjustment rod or into close contact through an air layer to adjust the temperature.

[0004] As such a so-called injection stretch blow molding method and a temperature regulating rod used therefor, methods described in Patent Documents 1 and 2 have been proposed.

[0005] Patent Document 1 proposes a molding method and a temperature-regulating rod that restrict shrinkage and deformation of a preform while simultaneously adjusting the preform's temperature locally in the axial direction from the inside. Patent Document 2 points out the following problem: when the contact surface of the temperature-regulating rod with the preform is a smooth, mirror-finished surface, the appropriate temperature range is narrow, at 60 to 75°C. Outside this temperature range, the preform will bite the temperature-regulating rod, and proposes roughening the contact surface of the temperature-regulating rod with the preform.

[0006] Thus, the proposals made so far have been that the temperature regulating rod is used exclusively for regulating the temperature of the preform, and that it is not recommended to partially change the wall thickness of the molded product by using the temperature regulating rod.

[0007] Injection-stretch blow molding products may have a structure in which the bottom wall thickness partially varies, as described in Patent Document 3, but the container sidewall generally has a constant wall thickness. Molded products with recessed and raised surfaces on the container sidewall are also known, but these have a constant wall thickness, and there are no known molded products in which the sidewall thickness partially varies.

[0008]

Prior technical literature

[0009] [Patent Literature]

[0010] [Patent Document 1] International Publication No. 222 / 181618 Pamphlet

[0011] [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-103611

[0012] [Patent Document 3] Japanese Patent Application Laid-Open No. 5-330535 Summary of the Invention

[0013] [Problems to be solved by the invention]

[0014] An object of the present invention is to provide an injection stretch blow molding method capable of obtaining a molded product having a variety of shapes by partially changing the thickness of the side wall of the molded product.

[0015] Another object of the present invention is to provide a temperature regulating rod capable of achieving changes in the unevenness and thickness of the molded product through the surface shape.

[0016]

Measures to solve the problem

[0017] The present invention provides a molding method for injection stretch blow molding, which performs molding while controlling the temperature of a preform using a temperature regulating rod, wherein, as the above-mentioned temperature regulating rod, by using a temperature regulating rod having an outer surface convex and concave at least on the side surface of the rod, an inner surface convex and concave is formed on the inner surface side of at least the side wall of the molded product, so that the wall thickness of the above-mentioned side wall is partially changed.

[0018] During implementation, injection stretch blow molding can be performed, wherein the process comprises an injection molding process, a temperature adjustment process, a stretch blow molding process and a removal process. The injection molding process preliminarily molds a cylindrical preform with plasticized material; the temperature adjustment process adjusts the temperature of the preform after the injection molding process by the temperature adjustment rod; the stretch blow molding process blows pressurized air into the preform after the temperature adjustment process from a nozzle in a closed mold and performs stretch blow molding; the removal process removes the product that has been cooled and solidified in the stretch blow molding process.

[0019] In addition, the present invention provides a temperature regulating rod, which is a temperature regulating rod used in the above-mentioned injection stretch blow molding method. The above-mentioned temperature regulating rod has the above-mentioned rod side facing the cylindrical pre-molded product that is pre-molded in the injection molding process, and the surface of the above-mentioned rod side is a smooth surface or a finely rough surface.

[0020] In addition, the surface of the side surface of the rod is a rough surface or a smooth surface having a roughness equal to or finer than the grain size of #300 of the sandpaper.

[0021] The outer surface projections and depressions may be projections and depressions extending in the axial direction of the temperature adjustment rod, projections and depressions extending in the circumferential direction of the temperature adjustment rod, or projections and depressions extending at an angle to the axial direction of the temperature adjustment rod.

[0022] Effects of the Invention

[0023] The present invention can provide an injection stretch blow molding method capable of obtaining a molded product having a variety of shapes by partially changing the thickness of the side wall of the molded product.

[0024] Furthermore, the present invention can provide a temperature regulating rod capable of realizing changes in the concavity and convexity and the wall thickness of the molded article by means of the surface shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is an explanatory diagram of a blow molding device according to one embodiment of the present invention.

[0026] Figure 2 (A) is a front view of a temperature adjustment rod according to an embodiment of the present invention; (B) is a cross-sectional view thereof; and C is a perspective view of a molded product.

[0027] Figure 3 (A) is a longitudinal sectional view of a conventional temperature regulating rod; (B) is a front view and a sectional view thereof; (C) is a front view and a sectional view of a temperature regulating rod according to another embodiment of the present invention; (D) is a front view and a sectional view of a temperature regulating rod according to yet another embodiment of the present invention; (E) is a front view and a sectional view of a temperature regulating rod according to yet another embodiment of the present invention.

[0028] Figure 4 (A) is a front view and a cross-sectional view of a temperature regulating rod according to another embodiment of the present invention; (B) is a front view and a cross-sectional view of a temperature regulating rod according to another embodiment of the present invention; (C) is a front view and a cross-sectional view of a temperature regulating rod according to another embodiment of the present invention.

[0029] Figure 5 (A) is a front view and a cross-sectional view of a temperature regulating rod according to another embodiment of the present invention; (B) is a front view and a cross-sectional view of a temperature regulating rod according to another embodiment of the present invention; (C) is a front view and a cross-sectional view of a temperature regulating rod according to another embodiment of the present invention.

[0030] Figure 6(A) is a front view and a cross-sectional view of a temperature adjustment rod according to another embodiment of the present invention; (B) is a front view of a temperature adjustment rod according to another embodiment of the present invention.

[0031] Figure 7 (A) is a front view and a cross-sectional view of a temperature regulating rod according to another embodiment of the present invention; (B) is a front view and a cross-sectional view of a temperature regulating rod according to another embodiment of the present invention; (C) is a front view and a cross-sectional view of a temperature regulating rod according to another embodiment of the present invention.

[0032] Figure 8 It is related Figure 7 (A) is a perspective view of a temperature adjustment rod according to an embodiment. DETAILED DESCRIPTION

[0033] Modes for carrying out the invention

[0034] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The shapes, sizes, etc. of the elements shown in the drawings are schematic and do not represent actual shapes, sizes, etc. In addition, the same elements are generally given the same reference numerals in the drawings for description.

[0035] exist Figure 1 The blow molding device 20 of this embodiment schematically shown in FIG. 1 is a blow molding device that utilizes the heat (internal heat) retained during injection molding to perform blow molding without cooling the preform to room temperature. Figure 2 The device is a thermal parisson method for forming a molded product 11 such as a container. Figure 2 The container (C) is a structure representing an example of a molded product 11, which includes a bottom end portion 13 including the bottom of the container, a mouth portion 14 of the container, a neck portion 15, a shoulder portion 16, and a tubular main body portion 17 between the bottom end portion 13 and the shoulder portion 16.

[0036] This blow molding device 20 includes an injection molding unit 21, a temperature control unit 22, a blow molding unit 23, a take-out unit 24, and a conveying mechanism 26. The injection molding unit 21, the temperature control unit 22, the blow molding unit 23, and the take-out unit 24 are arranged at positions rotated by a predetermined angle (e.g., 90 degrees) about the conveying mechanism 26.

[0037] (Transportation mechanism 26)

[0038] The conveying mechanism 26 includes a transfer plate 28 that moves in a rotational manner around a central axis. One or more holding portions (not shown) are arranged at predetermined angles on the transfer plate 28, and the holding portions detachably hold preforms (not shown) or Figure 2The neck portion 15 of the molded article 11, such as a resin container, is shown. The transport mechanism 26 transports the preform or molded article 11, whose neck portion is held by the holding section, in the order of the injection molding section 21, the temperature control section 22, the blow molding section 23, and the removal section 24 by rotating the transfer plate 28 90 degrees at a time. Furthermore, the transport mechanism 26 includes a lifting mechanism (a mold opening and closing mechanism in the vertical direction) and a mold opening mechanism in the holding section, and also performs operations such as lifting and lowering the transfer plate 28 and demolding operations in the injection molding section 21.

[0039] (Injection Molding Process: Injection Molding Section 21)

[0040] The injection molding section 21 includes an injection cavity mold and an injection core mold (not shown) and manufactures a preform. The injection molding section 21 is connected to an injection device 25 that supplies a resin material serving as a raw material for the preform.

[0041] During the injection molding process in the injection molding unit 21, the injection cavity mold, the injection core mold, and the holding portion of the conveyor mechanism 26 are closed to form a mold space in the shape of the preform. The injection molding unit 21 manufactures the preform by flowing resin material from the injection device 25 into this preform-shaped mold space.

[0042] For example, the preform may be a cylindrical preform with one end open and the other end closed, for example. A neck is formed at the end portion on the open side of the preform.

[0043] The molded article 11 and preformed article materials are thermoplastic synthetic resins, and can be appropriately selected depending on the intended use of the molded article 11. Specific examples of the materials include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (acid-modified copolyester), Tritan (copolyester, Tritan (registered trademark): a polyester manufactured by Eastman Chemical Company), PP (polypropylene), PE (polyethylene), PC (polycarbonate), PPSU (polyphenylene sulfone resin), PES (polyethersulfone resin), PS (polystyrene), COP / COC ((cycloolefin polymer) / (cycloolefin copolymer), a cyclic olefin polymer), PMMA (polymethyl methacrylate: acrylic acid), and PLA (polylactic acid).

[0044] Furthermore, even when the mold of the injection molding section 21 is opened, the holding portion of the conveying mechanism 26 does not release the preforms but continues to hold them for conveyance. The number of preforms that can be simultaneously molded in the injection molding section 21 (i.e., the number of molded articles 11 that can be simultaneously molded in the blow molding device 20) can be appropriately set.

[0045] (Temperature Adjustment Process: Temperature Adjustment Section 22)

[0046] The temperature control section 22 equalizes the temperature of the preforms produced by the injection molding section 21 and eliminates temperature deviations, thereby adjusting the temperature of the preforms to a temperature suitable for blow molding (e.g., approximately 90°C to 105°C) and a temperature distribution suitable for the shape of the molded article 11. The temperature control section 22 also cools the high-temperature preforms after injection molding.

[0047] Although not shown in the figure, the temperature adjustment part 22 has a cavity mold (temperature adjustment pot type, heating pot type) that can accommodate the preform and a temperature adjustment rod 31 as a mold component inserted into the inner side of the preform. The cavity mold has a space for temperature adjustment that is roughly the same shape as the outer shape of the preform manufactured by the injection molding part 21. The cavity mold can also use a plurality of molds that are divided into an upper mold, a middle mold, and a lower mold in the axial direction of the preform. Heating components such as belt heaters (ring heaters) and rod heaters are respectively installed on the cavity mold, and are maintained at a specified temperature by the heating components. The temperature of the preform is adjusted by heating the outer peripheral side of the preform with heat from this cavity mold. The cylindrical main body of the heated preform shrinks and deforms toward the inner diameter side and the neck side. In addition, by changing the temperature of the heating components of each section, the temperature distribution of the preform in the axial direction can also be changed.

[0048] In the temperature adjustment section 22 , the cavity mold and the temperature adjustment rod 31 perform temperature adjustment so as to bring the temperature of the preform close to a temperature suitable for final blow molding.

[0049] The temperature adjustment rod 31 is configured to be movable forward and backward in the axial direction relative to the preform by the temperature adjustment section 22. The temperature adjustment rod 31 includes a base portion 32 supported by the temperature adjustment section 22 and a main body portion 33 on the front end side.

[0050] During this temperature adjustment process, the transfer plate 28 descends, placing the preform held in the holding portion within the cavity mold. Furthermore, the temperature adjustment rod 31 of the support base 32 descends and is inserted into the preform, adjusting the preform's temperature to a level suitable for blow molding. This also reduces temperature deviations that may occur during injection molding.

[0051] The diameter of the main body 33 of the temperature control rod 31 is set to be smaller than the inner diameter of the preform. Furthermore, the tip of the temperature control rod 31 inserted into the preform contacts the bottom of the preform. The axial length of the temperature control rod 31 is set to the length assuming the shrinkage of the preform from the time it is transported from the injection molding unit 21 to the time the temperature control rod 31 is inserted.

[0052] Although not shown, a flow path for a temperature-control medium is formed along the axial direction within the temperature-control rod 31. The temperature-control medium flowing within the temperature-control rod 31 maintains the temperature of the temperature-control rod 31 at a predetermined temperature. The temperature-control rod 31 is set to a lower temperature than the preform, and the preform is cooled by the temperature-control rod 31. However, the temperature-control rod 31 can also be used to heat the preform.

[0053] The main body 33 of the temperature control rod 31 has an outer peripheral surface that is inserted into the preform and faces the inner peripheral surface of the preform. The outer peripheral surface of the main body 33 can be configured to have at least one of a portion that contacts the inner peripheral surface of the preform and a portion that faces the inner peripheral surface of the preform through an air layer instead of direct contact. The temperature of the main body 33 of the temperature control rod 31 is transferred to the preform through direct contact or through an air layer. Alternatively, a tip member can be detachably provided on the outer peripheral surface or the tip of the main body 33.

[0054] The main body 33 of the temperature control rod 31 in the embodiment of the present invention has outer surface projections and depressions 34 (concave portions 35 and convex portions 36) on the side surface of the cylindrical rod. These outer surface projections and depressions 34 form inner surface projections and depressions 12 on the inner surface of at least the sidewall (trunk portion 17) of the molded article 11, which is obtained by the stretch blow molding process performed by the blow molding unit 23 described below. The inner surface projections and depressions 12 of the molded article 11 formed by these outer surface projections and depressions 34 of the temperature control rod 31 are characterized by not the constant wall thickness of containers produced by conventional multiple injection stretch blow molding processes, but rather by the partial variation in the wall thickness of the molded article 11's sidewall. Therefore, they do not include the fine surface projections and depressions that are produced by roughening the surface of the temperature control rod facing the preform to achieve a constant wall thickness, as is shown in Patent Document 2.

[0055] The outer surface irregularities 34 of the main body 33 of the temperature control rod 31 are represented by the height difference between the concave portion 35 and the convex portion 36 in the circumferential direction of the concave portion. This height difference can be appropriately adjusted to partially alter the thickness of the sidewall of the molded article 11. Specifically, while it depends on the overall thickness of the molded article's sidewall, it is preferably between 0.1 mm and 6.0 mm. To achieve a more significant thickness difference, it is preferably at least 1.0 mm. It is preferably adjusted to suit various conditions, such as the type of resin, molding conditions, and the shape and size of the molded article 11. Furthermore, the surface morphology of the outer surface irregularities 34 of the main body 33 can be smooth, similar to conventional temperature control rods, but fine irregularities can also be formed, for example, with a roughness equal to or finer than #300 grit on sandpaper. Furthermore, regarding the molded product 11 including the portion corresponding to the bottom end 13 and the opening end 17 of the molded product 11 , there is no problem in concurrently applying other technologies such as conventional technologies related to the molding method and the temperature regulating rod.

[0056] In addition, the side surface concave-convex 34 can be implemented in various forms. Figure 2 As shown in (A) and (B), it can be implemented as a concave-convex shape extending in the axial direction of the temperature adjustment rod 31. This concave-convex shape has concave parts 35 and convex parts 36 appearing alternately in the circumferential direction, but the positions in the circumferential direction are staggered at the upper and lower parts of the main body 33 of the temperature adjustment rod 31. Figure 2 As shown in (C), on the inner side surface of the main body 17 of the molded product 11, the inner side bumps 12 are formed by the outer side bumps 34. On the other hand, the outer peripheral surface of the main body 17 of this molded product 11 is cylindrical with a uniform diameter, and the wall thickness is large in the convex part 36 of the inner side bumps 12, and small in the concave part 35. In addition, the shape of the outer peripheral surface of the main body 17 of the molded product 11 is mainly determined by the blow cavity mold of the blow molding part 23 in the subsequent stretch blow molding process, but in addition to the cylindrical shape, it can be implemented with various bumps and concave shapes like the previous molded products, and it can also be implemented by changing the overall shape of the molded product 11 to various shapes such as a square cylinder shape. In other words, when implementing the present invention, the shape of the inner peripheral surface can be changed regardless of the shape of the outer peripheral surface of the main body 17 of the molded product 11.

[0057] Figures 3 to 7 Various modification examples of the form of the unevenness 34 on the outer surface of the temperature adjustment rod 31 are shown.

[0058] Figure 3 FIG. 3 shows an example in which the outer surface concavo-convex convex 34 extending in the axial direction of the temperature regulating rod is formed over substantially the entire length of the main body 33. Figure 3In (A) and (B), the temperature adjustment rod 31 without the outer surface irregularities 34 is shown as a reference for comparison.

[0059] Figure 3 The temperature adjustment rod 31 of (C) has recesses 35 formed at intervals of 90 degrees, and portions between the recesses 35 are formed as convex portions 36 .

[0060] Figure 3 The temperature adjustment rod 31 of (D) is formed with relatively wide recesses 35 at intervals of 60 degrees, and the portions between the recesses 35 are formed into convex portions 36.

[0061] Figure 3 The temperature adjustment rod 31 of (E) has recesses 35 formed at intervals of 60 degrees, and portions between the recesses 35 are formed into projections 36 of the same width.

[0062] Figure 4 The temperature adjustment rod 31 of (A) has a concave-convex shape extending in the axial direction of the temperature adjustment rod, with planar concave portions 35 formed every 36 degrees, and portions between the concave portions 35 being formed into curved convex portions 36.

[0063] Figure 4 The temperature adjustment rod 31 of (B) is formed with arc-shaped recessed portions 35 at intervals of 36 degrees, and the portions between the recessed portions 35 are formed into convex portions 36.

[0064] Figure 4 The temperature adjustment rod 31 of (C) is formed with groove-shaped angular recesses 35 at intervals of 36 degrees, and the portions between the recesses 35 are formed into curved convex portions 36.

[0065] Figure 5 The temperature adjustment rod 31 of (A) has a concave-convex shape extending in the axial direction of the temperature adjustment rod, with planar concave portions 35 formed every 30 degrees and portions between the concave portions 35 being formed into curved convex portions 36 .

[0066] Figure 5 The temperature adjustment rod 31 of (B) is formed with arc-shaped recessed portions 35 at intervals of 30 degrees, and the portions between the recessed portions 35 are formed into convex portions 36.

[0067] Figure 5 The temperature adjustment rod 31 of (C) is formed with groove-shaped angular recesses 35 at intervals of 30 degrees, and the portions between the recesses 35 are formed into curved convex portions 36.

[0068] Figure 6The temperature regulating rod 31 of (A) is formed into a concave-convex shape extending in the axial direction of the temperature regulating rod at the upper, middle and lower sections, with relatively wide recesses 35 formed every 60 degrees, and the parts between the recesses 35 are made into convex sections 36. The middle section is formed in a circumferentially offset position from the upper and lower sections.

[0069] Figure 6 The temperature adjustment rod 31 of (B) has a concavo-convex shape extending in the circumferential direction of the temperature adjustment rod, and concave portions 35 and convex portions 36 are formed alternately in the axial direction.

[0070] Figure 7 The temperature adjustment rod 31 of (A) is a spiral concave-convex shape extending at an angle with respect to the axial direction of the temperature adjustment rod. Concave portions 35 are formed at intervals of 90 degrees, and portions between the concave portions 35 are formed as convex portions 36. Figure 8 A perspective view showing the temperature adjustment rod 31 is shown.

[0071] Figure 7 The temperature regulating rod 31 of (B) is a spiral concave-convex shape extending at an angle relative to the axial direction of the temperature regulating rod, with recesses 35 formed every 90 degrees, and the portion between the recesses 35 being made into a convex portion 36, but the upper and lower ends thereof being made into a structure extending in the axial direction of the temperature regulating rod.

[0072] Figure 7 The temperature adjustment rod 31 of (C) is in a concave-convex shape extending in the axial direction of the temperature adjustment rod, with recesses 35 formed every 90 degrees in the middle of the axial direction, and portions between the recesses 35 being formed as convex portions 36.

[0073] In addition, the form of the outer surface concavo-convex 34 is not limited to the example in the figure, and can be changed in various ways. For example, any one of the concave portion 35 and the convex portion 36 can be made into an island structure, or made into a structure in the shape of text, a symbol, or a figure, or made into an amorphous pattern.

[0074] (Stretch Blow Molding Process: Blow Molding Section 23)

[0075] return Figure 1 The blow molding section 23 performs stretch blow molding on the preform whose temperature is adjusted by the temperature adjustment section 22 to produce a molded product 11 such as a container.

[0076] The blow molding unit 23, although not shown, includes a blow cavity mold, a bottom mold, an extension rod, and an air introduction member (a blow core mold, all not shown) as a pair of split molds corresponding to the shape of the molded article 11. The blow molding unit 23 blow-moldes the preform while extending it. This forms the preform into the shape of the blow cavity mold, producing the molded article 11, such as a container.

[0077] In detail, in the blow molding section 23, the blow cavity mold is first closed, and the preform is accommodated in the mold space. The air introduction member (blow core) is lowered so that the air introduction member contacts the neck of the preform. Next, the extension rod (longitudinal axis extension member) is lowered to suppress the bottom of the preform from the inside. While the longitudinal axis is extended as needed, blow air is supplied from the air introduction member to extend the preform in the transverse direction. As a result, the preform is expanded and shaped in close contact with the mold space of the blow cavity mold, and blow-molded into a molded product 11. In addition, the bottom mold is on standby at a position below the preform that does not contact the bottom of the preform before the blow cavity mold is closed, and rises quickly to the molding position before or after the mold is closed.

[0078] The preform expands in close contact with the mold space of the blow cavity mold, and its outer circumference is shaped according to the contours of the blow cavity mold. Meanwhile, as previously described, during the temperature adjustment process, the outer contours 34 of the temperature adjustment rod 31 impart contours and a temperature difference to the inner circumference of the preform. As a result, reflecting these contours and temperature differences, inner contours 12, which vary with the wall thickness, are formed on the inner circumference of the molded article 11 during this blow molding process.

[0079] (Taking out process: taking out part 24)

[0080] The removal section 24 is configured to release the neck portion 15 of the molded article 11 produced by the blow molding section 23 from the holding portion and remove the molded article 11 to the outside of the blow molding apparatus 20. When blow molding in the blow molding section 23 is completed, the blow cavity mold and the bottom mold are opened. This allows the molded article 11 to be removed from the blow molding section 23. The transfer plate 28 of the conveying mechanism 26 rotates to transport the molded article 11 to the removal section 24. In the removal section 24, the neck portion 15 is released from the holding portion, and the molded article 11 is removed from the blow molding apparatus 20.

[0081] The present invention is not limited to the above-mentioned embodiment. Various improvements and design changes can be made within the scope of the purpose of the present invention. The shape of the temperature adjustment rod can also be variously changed according to the type, purpose, and shape of the molded product 11.

[0082]

Explanation of symbols

[0083] 11: Molded products

[0084] 12: Concave and convex inner surface

[0085] 13: Near the bottom end

[0086] 14: Mouth

[0087] 15: Neck

[0088] 16: Shoulders

[0089] 17: Main cadre

[0090] 20: Blow molding device

[0091] 21: Injection molding department

[0092] 22: Temperature adjustment unit

[0093] 23: Blow molding department

[0094] 24: Take-out section

[0095] 25: Injection molding device

[0096] 26: Transport Agency

[0097] 28: Transfer plate

[0098] 31: Temperature adjustment lever

[0099] 32: Base

[0100] 33: Main body

[0101] 34: Concave and convex outer surface

[0102] 35: concave part

[0103] 36: Convex part.

Claims

1. A method for injection stretch blow molding, wherein the molding is performed while controlling the temperature of the preform using a temperature regulating rod, characterized in that: By using a temperature regulating rod having outer surface projections and depressions at least on a rod side surface, inner surface projections and depressions are formed on at least the inner surface of the side wall of the molded article, thereby partially changing the thickness of the side wall.

2. The injection stretch blow molding method according to claim 1, characterized in that: It has injection molding process, temperature adjustment process, stretch blow molding process and removal process. The injection molding process preliminarily molds a cylindrical preform from plasticized material. The temperature adjustment step is to adjust the temperature of the preformed product after the injection molding step by the temperature adjustment rod; In the stretch blow molding step, the preform after the temperature adjustment step is blown into a closed mold through a nozzle to perform stretch blow molding. This removal process removes the product that has been cooled and solidified in the stretch blow molding process.

3. A temperature adjustment rod, characterized in that: The temperature regulating rod is a temperature regulating rod used in the injection stretch blow molding method according to claim 1, wherein the temperature regulating rod comprises a rod side surface facing a cylindrical preformed product preformed in an injection molding process. The surface of the side surface of the rod is a smooth surface or a finely rough surface.

4. The temperature adjustment rod according to claim 3, characterized in that: The surface of the side surface of the rod is a rough surface or a smooth surface having a roughness equal to or finer than #300 of the grain size of the surface of sandpaper.

5. The temperature regulating rod according to claim 3 or 4, characterized in that: The outer surface projections and depressions may be projections and depressions extending in the axial direction of the temperature adjustment rod, projections and depressions extending in the circumferential direction of the temperature adjustment rod, or projections and depressions extending at an angle to the axial direction of the temperature adjustment rod.

Images