Method for producing molded body and molded body

Abstract

To provide a method for manufacturing a molded product with a small thickness and a molded product.SOLUTION: A method for manufacturing a molded product includes: a step of preparing a molten resin 2 containing supercritical fluid 21; and a step of molding a molded product from the molten resin 2 by compression molding or injection molding. A minimum thickness of the molded product is 0.3 mm or less.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing a molded body and the molded body. [Background technology]

[0002] Polyesters such as polyethylene terephthalate are used in molded articles constituting various products because they are inexpensive and have excellent mechanical properties, chemical stability, heat resistance, gas barrier properties, transparency, etc. For example, they are widely used in the manufacture of containers for filling beverages and the like.

[0003] As a method for producing such molded articles such as containers, a method is known in which a polyester preform is prepared and then blow-molded using this preform to produce the molded article (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-178801 Summary of the Invention [Problem to be solved by the invention]

[0005] From the viewpoint of reducing the amount of materials required for producing a molded body and thereby reducing the environmental load, there is a demand for producing a molded body with a smaller thickness.

[0006] The present disclosure has been made in consideration of these points, and has an object to provide a molded body with a small thickness. [Means for solving the problem]

[0007] A method for manufacturing a molded body according to one embodiment includes the steps of: preparing a molten resin containing a supercritical fluid; and forming a molded body from the molten resin by compression molding or injection molding, In the method for producing a molded body, the molded body has a minimum thickness of 0.3 mm or less.

[0008] In the method for manufacturing a molded article according to one embodiment, the molten resin may contain polyethylene terephthalate.

[0009] In the method for manufacturing a molded body according to one embodiment, the molded body may have a minimum thickness of 0.15 mm or less.

[0010] A molded body according to one embodiment is made of a resin containing bubbles and has a minimum thickness of 0.3 mm or less, In the molded article, the maximum diameter of the bubbles is 0.05 mm or less.

[0011] A molded article according to one embodiment is made of a resin containing bubbles and has a minimum thickness of 0.3 mm or less, 1 mm of the cross section of the molded body 2 The number of bubbles contained per unit area is 400 or more and 6000 or less.

[0012] A molded article according to one embodiment is made of a resin containing bubbles and has a minimum thickness of 0.3 mm or less, In the molded article, 80 mass % or more of the gas contained in the bubbles is nitrogen or carbon dioxide.

[0013] In the molded article according to one embodiment, the minimum thickness may be 0.15 mm or less.

[0014] In one embodiment of the molded article, the resin may include polyethylene terephthalate. [Effects of the Invention]

[0015] According to the present disclosure, a molded body having a small thickness can be provided. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view showing a molded article according to one embodiment. [Figure 2] FIG. 2 is a vertical cross-sectional view showing a molded body according to one embodiment. [Figure 3] FIG. 3 is an enlarged cross-sectional view showing a part of the molded body of FIG. [Figure 4] FIG. 4 is a diagram showing a method for manufacturing a molded body according to one embodiment. [Figure 5] FIG. 5 is a diagram showing a method for manufacturing a molded body according to one embodiment. [Figure 6] FIG. 6 is a diagram showing a method for manufacturing a molded body according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] An embodiment will now be described with reference to the drawings. FIGS. 1 to 6 are diagrams illustrating one embodiment. The following figures are schematic diagrams. Therefore, the size and shape of each part are appropriately exaggerated for ease of understanding. Furthermore, appropriate modifications can be made without departing from the technical concept. In the following figures, identical parts are denoted by the same reference numerals, and some detailed descriptions may be omitted. Furthermore, the numerical values, such as dimensions, and material names of each component described in this specification are examples of an embodiment, and are not limited to these and can be selected and used as appropriate. In this specification, terms specifying shapes or geometric conditions, such as "perpendicular," are interpreted not only strictly but also to include substantially the same state.

[0018] <Molded body> First, a molded body 1 according to the present embodiment will be described with reference to Figures 1 and 2. In this embodiment, a container 10 will be described as an example of the molded body 1. Figure 1 is a perspective view showing the container 10 according to the present embodiment. Figure 2 is a vertical cross-sectional view showing the container 10 according to the present embodiment. In this specification, "above" refers to the upper side when the container 10 is held upright (Figures 1 and 2). In this specification, "below" refers to the lower side when the container 10 is held upright.

[0019] The container 10 according to this embodiment is a container obtained by a manufacturing method of the molded body 1, which will be described later. In this embodiment, the container 10 comprises a body 11, a bottom 12, and a flange 13. The body 11 constitutes the side of the container 10 when it is upright. The bottom 12 is connected to the lower part of the body 11. The flange 13 is connected to the upper part of the body 11. The bottom 12 and the flange 13 are spaced apart.

[0020] The body portion 11 has a cylindrical shape. In the example shown in Figs. 1 and 2, the body portion 11 has a cylindrical shape with a substantially uniform diameter as a whole centered on the central axis CL. However, the shape of the body portion 11 is not limited to this. The body portion 11 may have a polygonal cylindrical shape such as a rectangular cylindrical shape or an octagonal cylindrical shape. The body portion 11 may have a cylindrical shape in which the outer diameter and inner diameter gradually increase toward the top.

[0021] The bottom 12 closes the lower end 11b of the cylindrical body 11. In the example shown in Figures 1 and 2, the bottom 12 has a substantially flat shape. However, the shape of the bottom 12 is not limited to a substantially flat shape. The bottom 12 may have the shape of a bottom of a conventionally known container, for example, a bottom shape including a protrusion protruding upward in the center.

[0022] The bottom 12 has a gate mark 12a. In this specification, the term "gate mark" refers to a mark such as a concavo-convex mark formed by a gate 44 (see FIG. 4) for injecting an injection resin when the molded body 1 is manufactured by injection molding as described below.

[0023] The flange portion 13 surrounds the upper end 11a of the body portion 11. The flange portion 13 is a portion to which a lid material (not shown) is joined. By joining the lid material to the flange portion 13, a closed storage space is formed between the lid material and the body portion 11 and bottom portion 12 of the container 10. In this case, the lid material joined to the flange portion 13 may include a sealant layer having a relatively low adhesive strength, also known as an easy-peel sealant. By including such a sealant layer in the lid material, a user of the container 10 can easily peel the lid material from the container 10 and remove the contents of the container 10. An opening 16 is formed at the upper end 11a of the body portion 11. The flange portion 13 is formed around the entire periphery of the opening 16.

[0024] The capacity of the container 10 is not particularly limited, but may be, for example, 200 cm 3 The following is the result.

[0025] Next, the internal structure of the molded body 1 will be described. The molded body 1 according to this embodiment is made of a resin containing bubbles 14. FIG. 3 is an enlarged cross-sectional view showing an area designated by reference symbol III of the container 10 shown in FIG. 2. FIG. 3 illustrates the internal structure observed in the cross-section of the container 10, which was omitted in FIG. 2. As shown in FIG. 3, the container 10, which is the molded body 1, is made of a resin containing bubbles 14. In the example shown in FIG. 3, the container 10, which is the molded body 1, is made of a resin containing a resin main body portion 15 and bubbles 14 located within the resin main body portion 15.

[0026] The maximum diameter w1 of the bubbles 14 shown in FIG. 2 The number of bubbles 14 contained per unit area is, for example, 400 or more and 600 or less.

[0027] The composition of the gas contained in the bubbles 14 will be described. As an example, the composition of the gas contained in the bubbles 14 is different from the composition of air. For example, 80 mass % or more of the gas contained in the bubbles 14 of the molded body 1 may be nitrogen. Alternatively, 80 mass % or more of the gas contained in the bubbles 14 of the molded body 1 may be carbon dioxide.

[0028] The resin forming the molded body 1 is not particularly limited as long as it can be used to manufacture the molded body 1 using a manufacturing method for the molded body 1 described below. The resin forming the molded body 1 includes, for example, polyethylene terephthalate. In this case, the resin main body 15 may be made of polyethylene terephthalate.

[0029] In the container 10, which is the molded product 1 shown in FIG. 2, the body 11 has the minimum thickness of the molded product 1. That is, the thickness t1 of the body 11 is smaller than the thickness t2 of the flange 13. In the container 10 shown in FIG. 2, the minimum thickness is the thickness t1 of the body 11 in the radial direction of the container 10. The minimum thickness of the molded product 1 is 0.3 mm or less. The minimum thickness of the molded product 1 may be 0.15 mm or less, or may be 0.1 mm or less. When the minimum thickness of the molded product 1 is within the above numerical range, the amount of material required to manufacture the molded product 1 can be reduced, thereby reducing the environmental impact. The position at which the minimum thickness occurs is not limited to the body 11 of the container 10. For example, the position at which the minimum thickness occurs may be the flange 13 or the bottom 12. Furthermore, for example, the position at which the minimum thickness occurs may be closer to the opening 16 than the center of the body 11 in the direction of the central axis CL, or closer to the bottom 12 than the center in the direction of the central axis CL.

[0030] In this embodiment, the thickness t1 of the body portion 11 is constant in the vertical direction. The thickness t1 of the body portion 11 may be 0.9 times or less, 0.8 times or less, or 0.5 times or less the thickness t2 of the flange portion 13.

[0031] <Method of manufacturing molded body> Next, a method for manufacturing the molded body 1 of this embodiment will be described. In particular, a method for manufacturing a container 10 which is the molded body 1 shown in FIGS. 1 to 3 will be described. The method for manufacturing the molded body 1 includes a step of preparing a molten resin 2 containing a supercritical fluid 21, and a step of molding the molded body 1 from the molten resin 2. In this embodiment, first, in the step of preparing the molten resin 2 containing the supercritical fluid 21, the molten resin 2 is prepared by dissolving the supercritical fluid 21 in a molten resin main material 22. Hereinafter, in this embodiment, a step of molding the molded body 1 by injection molding will be described as an example of a step of molding the molded body 1 from the molten resin 2.

[0032] First, a description will be given of the foam molding apparatus 3 used in the method for producing the molded article 1 of this embodiment. Figure 4 is a diagram showing the foam molding apparatus 3 used in the method for producing the molded article 1 of this embodiment.

[0033] The foam molding apparatus 3 shown in FIG. 4 includes a mold section 40 and an injection device 30. The mold section 40 is a section where a molded body 1 is molded from a molten resin 2. As shown in FIG. 4, the mold section 40 includes a cavity-side mold 41 and a core-side mold 43 including a core 42. The cavity-side mold 41 may be a fixed mold fixed by a fixed platen (not shown). The core-side mold 43 may be a movable mold movably held by a movable platen (not shown). The inner surface of the cavity-side mold 41 has a shape corresponding to the outer surface of a container 10, which is the molded body 1 to be manufactured. The outer surface of the core 42 of the core-side mold 43 has a shape corresponding to the inner surface of the container 10. A gate (injection port) 44 for injecting the molten resin 2 is formed in the cavity-side mold 41 at a position corresponding to the bottom 12 of the container 10.

[0034] The injection device 30 includes a barrel 33 extending horizontally, a resin-based material supply unit 32 that supplies resin (e.g., pelletized resin) into the barrel 33, and a supercritical fluid generator 31 connected to the barrel 33 at a supercritical fluid supply unit 35. The barrel 33 has a cylindrical shape, and a cylindrical space 33A is formed therein. A first screw 34 and a second screw 36 are provided within the cylindrical space 33A. The first screw 34 and the second screw 36 are integrated with each other. The first screw 34 is located closer to the base end (the resin-based material supply unit 32 side) than the supercritical fluid supply unit 35. The second screw 36 is located closer to the tip end (the mold unit 40 side) than the supercritical fluid supply unit 35. The first screw 34 is provided with a spirally circumferential flight 34a. The flight 34a applies frictional force to the resin, which plasticizes the resin. A plurality of blades 36a are provided in an irregular arrangement on the second screw 36. The blades 36a mix the resin main material 22, which has been plasticized and put into a molten state, with the supercritical fluid 21.

[0035] The molded article 1 of this embodiment is manufactured using the foam molding apparatus 3 shown in Figure 4. Here, Figure 5 is a diagram showing the changes in the state of the molten resin 2 when the manufacturing method of the molded article 1 is carried out. The changes from (a) to (b) and (c) to (d) in Figure 5 correspond to the changes in the process of preparing the molten resin 2. The changes from (d) to (e) in Figure 5 correspond to the changes in the process of molding the molded article 1.

[0036] In the step of preparing the molten resin 2 containing the supercritical fluid 21, first, as shown in FIG. 5(a), the supercritical fluid 21 and a molten resin main material 22 are prepared.

[0037] The supercritical fluid 21 is a substance in a state where the intermolecular distance is short and the molecular motion is fast under high temperature and pressure conditions, and the substance has the properties of both a liquid and a gas. The material of the supercritical fluid 21 is, for example, nitrogen or carbon dioxide.

[0038] In the foam molding apparatus 3 shown in FIG. 4, the supercritical fluid 21 is generated in the supercritical fluid generating unit 31. Specifically, the supercritical fluid generating unit 31 has a nitrogen or carbon dioxide gas source such as a cylinder, and a booster pump. In this case, the supercritical fluid 21 can be generated by pressurizing the nitrogen or carbon dioxide supplied from the gas source with the booster pump. The method by which the supercritical fluid generating unit 31 generates the supercritical fluid 21 is not particularly limited, and any conventionally known method for generating the supercritical fluid 21 can be used depending on the material of the supercritical fluid 21.

[0039] The material used as the main resin material 22 is the material that forms the resin body 15 of the molded body 1 to be manufactured. For example, when manufacturing a molded body 1 in which the resin body 15 is made of polyethylene terephthalate as described above, polyethylene terephthalate is used as the main resin material 22.

[0040] In the foam molding apparatus 3 shown in Figure 4, the molten resin main material 22 is obtained by the following method. First, the unmolten resin main material 22, for example, the pellet-like resin main material 22, is supplied from the resin main material supply unit 32 into the cylindrical space 33A. Next, the first screw 34 is rotated to agitate the resin main material 22 in the cylindrical space 33A. This applies a frictional force to the resin main material 22, which plasticizes the resin main material 22, thereby obtaining the molten resin main material 22.

[0041] Next, as shown in Fig. 5(b), supercritical fluid 21 is injected into molten resin main material 22. In foam molding apparatus 3 shown in Fig. 4, supercritical fluid 21 generated in supercritical fluid generating unit 31 is supplied into cylindrical space 33A using supercritical fluid supply unit 35. In this way, supercritical fluid 21 can be injected into molten resin main material 22.

[0042] Next, the molten resin-based material 22 and the supercritical fluid 21 are mixed. In the foam molding apparatus 3 shown in FIG. 4, the molten resin-based material 22 and the supercritical fluid 21 are mixed by rotating the second screw 36. As a result, the supercritical fluid 21 diffuses into the molten resin-based material 22, as shown in FIG. 5(c). As the diffusion of the supercritical fluid 21 progresses in the molten resin-based material 22, the supercritical fluid 21 is dissolved in the molten resin-based material 22, as shown in FIG. 5(d). Here, the pressure in the cylindrical space 33A is maintained at a high pressure equal to or higher than the saturation pressure for dissolving the supercritical fluid 21 in the resin-based material 22. Therefore, the state in which the supercritical fluid 21 is dissolved in the resin-based material 22 is maintained in the cylindrical space 33A, as shown in FIG. 5(d).

[0043] Through the above steps, a molten resin 2 containing supercritical fluid 21 is obtained. In particular, a molten resin 2 is obtained in which supercritical fluid 21 is dissolved in a molten resin main material 22. When polyethylene terephthalate is used as the resin main material 22 as described above, the molten resin 2 contains polyethylene terephthalate.

[0044] After preparing the molten resin 2 containing the supercritical fluid 21, the molten resin 2 is molded into the molded body 1.

[0045] First, as shown in Fig. 6, the core 42 is inserted into the cavity-side mold 41 of the mold section 40. Then, the cavity-side mold 41 and the core-side mold 43 are clamped together.

[0046] Next, the molten resin 2 is injected into the space between the cavity-side mold 41 and the core 42. Here, FIG. 6 is a diagram showing the state in which the molten resin 2 has been injected into the space between the cavity-side mold 41 and the core 42. In FIG. 6, structures in the molten resin 2, such as gas bubbles 14, are not shown. At this time, with the cavity-side mold 41 and the core-side mold 43 clamped together, the molten resin 2 is injected into the space between the cavity-side mold 41 and the core 42 from an injection resin gate 44 provided in the cavity-side mold 41. The molten resin 2 injected from the gate 44 enters between the cavity-side mold 41 and the core 42.

[0047] In the process of molding the molded body 1 from the molten resin 2, the molten resin 2 is decompressed to a pressure lower than the saturation pressure of the supercritical fluid 21 with respect to the resin-based material 22. Here, the saturation pressure of the supercritical fluid 21 with respect to the resin-based material 22 refers to the saturation pressure at which the supercritical fluid 21 dissolves in the resin-based material 22. In this embodiment, the space between the cavity-side mold 41 and the core 42 is under a lower pressure than the cylindrical space 33A. Therefore, the molten resin 2 injected into the space between the cavity-side mold 41 and the core 42 is decompressed. During the decompression of the molten resin 2, the supercritical fluid 21 dissolved in the resin-based material 22 becomes supersaturated in the cylindrical space 33A and foams, as shown in FIG. 5(d), and then generates fine bubbles 14 as shown in FIG. 5(e).

[0048] Next, the molten resin 2 is introduced into the gap between the cavity-side mold 41 and the core 42, and then cooled and solidified. The solidification of the molten resin 2 stops the generation and growth of the bubbles 14. This produces a molded body 1 made of resin containing fine bubbles 14 as shown in FIG. 3.

[0049] Next, the effects of the method for manufacturing the molded body 1 according to this embodiment will be described. In the method for manufacturing the molded body 1 according to this embodiment, the molded body 1 is molded from a molten resin 2 containing a supercritical fluid 21. As a result, the molten resin 2 is depressurized when molding the molded body 1, causing the supercritical fluid 21 to foam and generate fine bubbles 14. The bubbles 14 generated by foaming the supercritical fluid 21 are finer than the bubbles generated by air mixing in during normal molding. It has been confirmed that a molten resin 2 containing such fine bubbles 14 has higher fluidity than a resin that does not contain such bubbles 14. Therefore, when molding the molded body 1, the molten resin 2 is more likely to flow throughout the entire region where the molded body 1 is to be formed. This makes it possible to suppress the occurrence of so-called short shots.

[0050] According to the manufacturing method of the molded body 1 of this embodiment, even when the thickness of the molded body 1 to be manufactured is small, the occurrence of short shots can be suppressed while manufacturing the molded body 1 because of the high fluidity of the molten resin 2. For example, it is possible to manufacture a molded body 1 having the above-mentioned minimum thickness of 0.3 mm or less, particularly 0.15 mm or less, and particularly 0.1 mm or less.

[0051] Furthermore, according to the manufacturing method of the molded body 1 of this embodiment, even when molding a molded body 1 having a shape that is thought to be prone to short shots during manufacturing, the molded body 1 can be manufactured while suppressing the occurrence of short shots. For example, the container 10, which is the molded body 1 shown in FIG. 2, has a bottom 12 having a gate mark 12a and a flange portion 13 spaced from the bottom 12, and a body portion 11 connected to the flange portion 13 and the bottom 12. The thickness t1 of the body portion 11 is smaller than the thickness t2 of the flange portion 13. Thus, when manufacturing a molded body 1 having a second portion (body portion 11) thinner than the first portion (flange portion 13) between the portion having the gate mark 12a (bottom portion 12) and the first portion spaced from the portion having the gate mark 12a in an arbitrary cross section, the flow of the molten resin 2 may be obstructed in the second portion. For this reason, short shots are likely to occur during the manufacturing of the molded body 1. In contrast, according to the manufacturing method of the molded body 1 of this embodiment, even a molded body 1 having such a shape can be manufactured while suppressing the occurrence of short shots. The thickness of the second portion may be 0.9 times or less, 0.8 times or less, or 0.5 times or less the thickness of the first portion.

[0052] Furthermore, the molded body 1 manufactured by the manufacturing method for the molded body 1 according to the present embodiment is made of a resin containing bubbles 14, as shown in Fig. 3. Therefore, the density of the molded body 1 can be reduced by the volume occupied by the bubbles 14 in the resin. This allows the weight of the molded body 1 to be reduced.

[0053] Furthermore, in normal molding, particularly normal injection molding, when the molten resin is cooled and solidified between the molds, the molten resin shrinks unevenly due to solidification, which can result in sink marks, warping, etc. In contrast, according to the manufacturing method for molded body 1 according to this embodiment, when molten resin 2 is cooled and solidified, air bubbles 14 expand significantly in areas where main resin material 22 has significantly shrunk, thereby maintaining the overall shape of molded body 1. This makes it possible to suppress the occurrence of sink marks, warping, etc.

[0054] Furthermore, according to the manufacturing method of the molded body 1 according to the present embodiment, as described above, when the molten resin 2 is cooled and solidified, the bubbles 14 expand significantly in the areas where the main resin material 22 has significantly shrunk, thereby maintaining the overall shape of the molded body 1. This improves the dimensional accuracy of the molded body 1.

[0055] Another known method for producing thin molded articles such as containers using resin, particularly polyethylene terephthalate, involves preparing a preform by injection molding or the like and then blow molding the preform. However, blow molding increases the number of manufacturing steps, making the manufacturing process more complicated. In addition, it is difficult to ensure dimensional accuracy in the thickness of the molded article in blow molding.

[0056] In contrast, the manufacturing method of the molded article 1 according to this embodiment does not require blow molding, thereby reducing the number of steps. Furthermore, as described above, the dimensional accuracy of the molded article 1 can be improved. Furthermore, the manufacturing method of the molded article 1 according to this embodiment also makes it easy to manufacture a molded article 1 having different thicknesses in different parts depending on the strength required for each part. For example, as shown in FIG. 2, a container 10 can be easily manufactured in which the thickness t2 of the flange portion 13 is greater than the thickness t1 of the body portion 11.

[0057] The bubbles 14 in the produced molded body 1 are bubbles generated by foaming the supercritical fluid 21, and therefore the composition of the gas contained in the bubbles 14 may differ from that of air. For example, when nitrogen is used as the material for the supercritical fluid 21, 80 mass % or more of the gas contained in the bubbles 14 in the molded body 1 may be nitrogen, as described above. Furthermore, when carbon dioxide is used as the material for the supercritical fluid 21, 80 mass % or more of the gas contained in the bubbles 14 in the molded body 1 may be carbon dioxide, as described above.

[0058] As described above, one embodiment has been described with reference to specific examples, but the above-described specific examples are not intended to limit the embodiment. The above-described embodiment can be implemented with various other specific examples, and various omissions, substitutions, and modifications can be made without departing from the spirit of the embodiment.

[0059] Modifications of this embodiment will be described below. In the following description and the drawings used in the following description, parts that can be configured similarly to the above-described specific example will be designated by the same reference numerals as those used for the corresponding parts in the above-described specific example, and duplicated descriptions will be omitted.

[0060] (Variation 1) In the above-described embodiment, a method for manufacturing a molded body 1 has been described, in which the molded body 1 is molded by injection molding in the step of molding the molded body 1 from the molten resin 2. However, the method for molding the molded body 1 is not limited to injection molding. In the step of molding the molded body 1 from the molten resin 2, the molded body 1 may also be molded by compression molding. Molding of the molded body 1 by compression molding is performed, for example, as follows. First, a molten resin 2 containing a supercritical fluid 21 is prepared. Next, the molten resin 2 is placed in a cavity-side mold for compression molding. Then, the molten resin 2 is pressurized using a compression molding machine between the cavity-side mold and core-side mold for compression molding, and solidified.

[0061] (Variation 2) In the above-described embodiment and modified example, a method for manufacturing a molded body 1 that does not include blow molding has been described. However, the method for manufacturing a molded body 1 may include blow molding as a step. For example, a preform may be formed by injection molding a molten resin 2 containing a supercritical fluid 21, and then the preform may be blow molded to manufacture the molded body 1. In this case, a so-called hot parison method may be used, in which the preform is blow molded while maintaining the preheat for injection molding. Because the method for manufacturing a molded body 1 according to modified example 2 includes a step of stretching the preform by blow molding, the resistance of the manufactured molded body 1 to drop impacts, etc. may be improved compared to the method for manufacturing a molded body 1 according to the above-described embodiment.

[0062] The components disclosed in the above-described embodiment and each modification may be combined as needed, or some components may be omitted from all the components shown in the above-described embodiment and each modification. [Explanation of symbols]

[0063] 1. Molded body 10 containers 11 Torso 12 Bottom 12a Gate remains 13 Flange 14 Bubbles 15 Resin body 2. Molten resin 21 Supercritical fluid 22 Resin main material 3. Foam molding equipment 31 Supercritical fluid generation unit 32 Resin main material supply section 33 barrels 34 First screw 35 Supercritical fluid supply section 36 Second screw 40 Mold Department 41 Cavity side mold 42 cores 43 Core side mold 44 Gate (inlet)

Claims

1. preparing a molten resin containing a supercritical fluid; and forming a molded body from the molten resin by injection molding, The minimum thickness of the molded body is 0.3 mm or less, the molded body is a container including a cylindrical body portion, a bottom portion that closes a lower end of the body portion, and a flange portion that surrounds an upper end of the body portion and is spaced from the bottom portion, The body portion has the minimum thickness of the molded body, A method for manufacturing a molded body, in which, in the process of molding the molded body, the molded body is molded from the molten resin using a mold part in which a gate for injecting the molten resin is formed at a position corresponding to the bottom of the container.

2. The method for producing a molded article according to claim 1 , wherein the molten resin contains polyethylene terephthalate.

3. The method for producing a molded article according to claim 1 or 2, wherein the molded article has a minimum thickness of 0.15 mm or less.

4. A molded body made of a resin containing bubbles and having a minimum thickness of 0.3 mm or less, The maximum diameter of the bubbles is 0.05 mm or less, the molded body is a container including a cylindrical body portion, a bottom portion that closes a lower end of the body portion, and a flange portion that surrounds an upper end of the body portion and is spaced from the bottom portion, A molded body, wherein the body portion has the minimum thickness of the molded body.

5. A molded body made of a resin containing bubbles and having a minimum thickness of 0.3 mm or less, 1 mm of the cross section of the molded body ２ the number of bubbles contained per unit area is 400 or more and 600 or less, the molded body is a container including a cylindrical body portion, a bottom portion that closes a lower end of the body portion, and a flange portion that surrounds an upper end of the body portion and is spaced from the bottom portion, A molded body, wherein the body portion has the minimum thickness of the molded body.

6. A molded body made of a resin containing bubbles and having a minimum thickness of 0.3 mm or less, 80 mass% or more of the gas contained in the bubbles is nitrogen or carbon dioxide, the molded body is a container including a cylindrical body portion, a bottom portion that closes a lower end of the body portion, and a flange portion that surrounds an upper end of the body portion and is spaced from the bottom portion, A molded body, wherein the body portion has the minimum thickness of the molded body.

7. The molded article according to any one of claims 4 to 6, having a minimum thickness of 0.15 mm or less.

8. The molded article according to claim 4 , wherein the resin contains polyethylene terephthalate.

9. A molded body described in any one of claims 4 to 8, wherein the bottom has a gate mark.

Images