Molding molds for resin containers, and injection molding machines.

Abstract

To provide a mold for molding a resin container with a flanged mouth that prevents burrs.SOLUTION: A mold for molding a resin container is composed of an injection mold (38), a blow mold (39), and an intermediate mold (41). When the injection mold (38) and the intermediate mold (41) are clamped and injected, a parison (62) with a flanged mouth (64) formed from a first annular step (44) and an annular face (48) is molded. When the intermediate mold (41) is clamped with the blow mold (39), leaving the parison (62) in the intermediate mold (41), the flanged mouth (64) is compressed by a second annular step (58) and the annular face (48). The first annular step (44) has a side wall surface (45) for forming an outer surface (67) of the flanged mouth (64), which is connected to a parting line (PL). The second annular step (58) has a side wall surface (60) for contact with the outer surface (67), which is connected to the parting line (PL).SELECTED DRAWING: Figure 3F

Description

Technical Field

[0001] The present invention relates to a molding die and an injection blow molding machine that are adapted to form a resin container having a flange-shaped mouth portion by blow molding in which a parison is formed by injection molding and compressed air is supplied to the parison.

Background Art

[0002] Resin containers having a flange-shaped mouth portion are widely used as containers for containing and sealing beverages, foods, etc. Food, etc. is stored in the resin container, and a film-like lid is attached to the flange-shaped mouth portion. By doing so, food, etc. can be sealed and hygienically distributed.

[0003] A resin container having a flange-shaped mouth portion can be formed by a die for injection blow molding as described in, for example, Patent Document 1. That is, the die is composed of an injection molding die in which a recess is formed, an intermediate die provided with a core, and a blow molding die in which a recess is formed. First, the injection molding die and the intermediate die are clamped, and resin is injected to form a parison. Next, the mold is opened while leaving the parison on the core of the intermediate die. The intermediate die and the blow molding die are aligned and clamped. Then, the parison is sandwiched between the blow molding die and the intermediate die. When compressed air is supplied to the parison, a resin container having a flange-shaped mouth portion is formed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The flange-like opening of the resin container is formed in a parison molded from an injection mold and an intermediate mold, and the parison is then sandwiched between a blow mold and an intermediate mold. Since resin shrinks as the temperature decreases, the flange-like opening is initially formed with a slightly larger volume during injection molding. This compresses the flange-like opening of the parison when it is pressed down by the blow mold and the intermediate mold. This prevents sink marks from forming in the flange-like opening of the resin container. However, when the flange-like opening of the parison is pressed down by the blow mold and the intermediate mold, there is a risk that the resin in the flange-like opening may leak from the parting line between the blow mold and the intermediate mold. In other words, there is a risk of burr formation.

[0006] This disclosure provides a mold for molding a resin container equipped with a flange-shaped opening that prevents the generation of burrs.

[0007] Other challenges and novel features will become apparent from the description and accompanying drawings in this specification. [Means for solving the problem]

[0008] This disclosure comprises an injection molding die having a first recess and a first annular step portion around it; a blow molding die consisting of a plurality of segmented molds that, when combined, form a second recess and a second annular step portion; and an intermediate mold having a core with compressed air holes formed inside and an annular surface portion around it. When the injection molding die and the intermediate mold are clamped together and injected, a parison is formed, with a flange-like opening portion formed from the first annular step portion and the annular surface portion. When the blow molding die and the intermediate mold are clamped together, the flange-like opening portion is compressed by the second annular step portion and the annular surface portion, and the cavity formed from the second annular step portion and the annular surface portion has a smaller volume. Furthermore, this disclosure provides that the first annular step portion has an outer surface forming side wall surface for forming the outer circumferential surface of the flange-like opening portion of the parison, and the second annular step portion has an outer surface contact wall surface that contacts the outer circumferential surface. The side wall surface for forming the outer surface and the wall surface for contact with the outer surface are connected to the parting line. [Effects of the Invention]

[0009] This disclosure can prevent the generation of burrs. [Brief explanation of the drawing]

[0010] [Figure 1] This is a front view of an injection blow molding machine according to the first embodiment. [Figure 2] This is a front view showing a part of an injection blow molding machine and a part of a molding die according to the first embodiment. [Figure 3A] This is a front cross-sectional view showing the injection molding die and the intermediate mold of a molding die according to the first embodiment. [Figure 3B] This is a front cross-sectional view showing the injection molding die and the intermediate mold of a molding die according to the first embodiment. [Figure 3C] This is a front cross-sectional view showing the injection molding die and intermediate mold of the molding die according to the first embodiment, and a parison formed by injection molding. [Figure 3D] This is a front cross-sectional view showing the injection molding die, intermediate mold, and parison of a molding die according to the first embodiment. [Figure 3E] This is a front cross-sectional view showing the blow molding die, the intermediate mold, and the parison of a molding die according to the first embodiment. [Figure 3F] This is a front cross-sectional view showing the blow molding die, the intermediate mold, and the parison of a molding die according to the first embodiment. [Figure 3G] This is a front cross-sectional view showing the blow molding die, the intermediate mold, and the parison of a molding die according to the first embodiment. [Figure 3H] This is a front cross-sectional view showing a blow molding die, an intermediate mold, and a resin container of a molding die according to the first embodiment. [Figure 3I] This is a front cross-sectional view showing a blow molding die, an intermediate mold, and a resin container of a molding die according to the first embodiment. [Figure 4A]Front cross-sectional views showing a blow molding die, an intermediate die, and a part of a parison of the molding die according to the first embodiment. [Figure 4B] Front cross-sectional views showing a blow molding die, an intermediate die, and a part of a parison of the molding die according to the first embodiment. [Figure 5A] Front cross-sectional views showing a blow molding die, an intermediate die, and a part of a parison of the molding die according to the comparative example. [Figure 5B] Front cross-sectional views showing a blow molding die, an intermediate die, and a part of a parison of the molding die according to the comparative example. [Figure 6A] Front cross-sectional views showing a part of an injection molding die and an intermediate die of the molding die according to the second embodiment. [Figure 6B] Side view of a parison injection molded with the molding die according to the second embodiment. [Figure 6C] Cross-sectional view of a parison injection molded with the molding die according to the second embodiment, cut along section X-X in FIG. 6B. [Figure 6D] Cross-sectional view of a parison according to the first modification of the second embodiment. [Figure 6E] Cross-sectional view of a parison according to the second modification of the second embodiment. [Figure 7] Front cross-sectional views showing a blow molding die, an intermediate die, and a part of a parison of the molding die according to the modification of the first embodiment.

Mode for Carrying Out the Invention

[0011] Hereinafter, specific embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. For clarity of explanation, the following description and drawings are appropriately simplified. In each drawing, the same reference numerals are assigned to the same elements, and redundant descriptions are omitted as necessary. Also, there are parts where hatching is omitted so that the drawings do not become complicated.

[0012] [First Embodiment] <Injection blow molding machine> An injection blow molding machine 1 according to the first embodiment is shown in Figure 1. The injection blow molding machine 1 includes a mold clamping device 2 for clamping a molding die 30, which will be described later, an injection device 3 for injecting resin, a compressed air supply device 5 for supplying compressed air, and a controller 4 for controlling these.

[0013] <Mold clamping device> The mold clamping device 2 comprises a fixed platen 7 fixed to the bed B, and a plurality of mold plates slidably mounted on the bed B. Specifically, a movable platen 8, a mold clamping housing 9, and an intermediate platen 10 located between the fixed platen 7 and the movable platen 8. The fixed platen 7 and the mold clamping housing 9 are connected by a plurality of tie bars 11, 11, ... for example, four tie bars, and the movable platen 8 and the intermediate platen 10 are passed through by tie bars 11, 11, ... A mold clamping mechanism, or toggle mechanism 13 in this embodiment, is provided between the movable platen 8 and the mold clamping housing 9. Therefore, when the toggle mechanism 13 is driven, the movable platen 8 is driven in the left-right direction.

[0014] In the first embodiment, the intermediate platen 10 is composed of an intermediate platen support 15 and an intermediate platen body 16 that is rotatably, i.e., reversibly supported by the intermediate platen support 15. Between the intermediate platen support 15 and the movable platen 8, there is an intermediate platen opening / closing mechanism 17 that drives the intermediate platen 10 in the direction away from and towards the movable platen 8. Therefore, when the toggle mechanism 13 and the intermediate platen opening / closing mechanism 17 are driven in conjunction, the molding die 30, which will be described later, can be clamped, and similarly when driven in conjunction, the die can be opened.

[0015] <Injection device> The injection device 3 consists of a heating cylinder 19, a screw 20 located inside the heating cylinder 19, and a drive mechanism 22 that drives the screw 20. The heating cylinder 19 is equipped with a hopper 23 for supplying the injection material. An injection nozzle 24 is also provided at the tip of the heating cylinder 19.

[0016] <Mold> The molding die 30 according to the first embodiment is composed of a plurality of die groups. Specifically, it consists of an injection molding die group 31 provided on the fixed platen 7, a blow molding die group 32 provided on the movable platen 8, a first intermediate die group 34 provided on one side of the intermediate platen body 16, and a second intermediate die group 35 provided on the other side. Figure 2 shows a part of the clamping device 2 and a part of the molding die 30, where the injection molding die group 31 is composed of a plurality of injection molding dies 38, 38, ... The blow molding die group 32 is composed of the same number of blow molding dies 39, 39, ... as the injection molding dies 38, 38, ... of the injection molding die group 31. Similarly, the first intermediate die group 34 is composed of the same number of intermediate dies 41, 41, ... and the second intermediate die group 35 is also composed of the same number of intermediate dies 41, 41, ...

[0017] When the intermediate plate 10 is clamped in the position shown in Figure 2, that is, the first inversion position, the injection molding die group 31 and the first intermediate mold group 34 are clamped together, as are the blow molding die group 32 and the second intermediate mold group 35. On the other hand, when the intermediate plate 10 is inverted, that is, when it is clamped in the second inversion position, the injection molding die group 31 and the second intermediate mold group 35 are clamped together, as are the blow molding die group 32 and the first intermediate mold group 34.

[0018] <Injection mold> Figure 3A shows one injection mold 38 and one intermediate mold 41. The injection mold 38 has a first recess 43 and an annular stepped portion around the first recess 43, i.e., a first annular stepped portion 44. The first recess 43 is structured to form the main body of the parison, and the first annular stepped portion 44 is structured to form the flange-shaped opening of the parison. The first annular stepped portion 44 is equipped with a cylindrical outer surface forming side wall surface 45, and the outer surface of the flange-shaped opening is formed by this outer surface forming side wall surface 45. A distinctive feature of the injection mold 38 is that this outer surface forming side wall surface 45 is connected to the parting line PL. A runner 46 is connected to the first recess 43, and resin is injected from the injection device 3 (see Figure 1).

[0019] <Intermediate mold> As shown in Figure 3A, the intermediate mold 41 has a core 47 and an annular surface, or annular surface portion 48, surrounding the core 47. The core 47 is provided with compressed air holes 50, 50 for supplying compressed air. The compressed air supply device 5 (see Figure 1) is connected to the first intermediate mold group 34 and the second intermediate mold group 35, and supplies compressed air to the compressed air holes 50, 50 of the intermediate mold 41 (see Figure 3A) provided in each group. This enables blow molding, as will be explained later.

[0020] When the injection molding die 38 and the intermediate mold 41 are clamped together, an injection molding cavity, or parison molding cavity 52, is formed as shown in Figure 3B. The parison molding cavity 52 consists of two cavities: a body-forming cavity 53 that forms the main body of the parison, consisting of a first recess 43 and a core 47, and a mouth-forming cavity 54 that forms the flange-shaped mouth of the parison, consisting of a first annular step 44 and an annular surface 48. As will be explained later, a parison with a flange-shaped mouth is obtained by injection molding.

[0021] <Blow molding die> Figure 3E shows a blow molding die 39. In this embodiment, the blow molding die 39 is composed of two split dies 56, 56. When the split dies 56, 56 are joined together, the blow molding die 39 has a second recess 57 and a second annular stepped portion 58, which is an annular stepped portion. The second recess 57 is structured to form a container from a parison by blow molding, and the second annular stepped portion 58 is structured to press and compress the flange-shaped opening of the parison, as will be explained in detail later. The second annular stepped portion 58 is provided with a cylindrical outer peripheral contact side wall surface 60, which contacts the outer peripheral surface of the flange-shaped opening. A feature of this disclosure is that the outer peripheral contact side wall surface 60 is connected to the parting line PL in the blow molding die 39.

[0022] <Injection blow molding method> A method for molding a resin container using the injection molding machine 1 (see Figure 1) and molding die 30 according to the first embodiment will be described. As shown in Figure 2, the intermediate platen 10 is set to the first inversion position. Then, the injection molding die group 31 and the first intermediate die group 34 face each other, and as shown in Figure 3A, the respective injection molding dies 38 and intermediate dies 41 are aligned. When the molds are clamped, the injection molding dies 38 and intermediate dies 41 are clamped together as shown in Figure 3B. As described above, a parison molding cavity 52 is formed, consisting of a cavity 53 for forming the main body and a cavity 54 for forming the mouth.

[0023] When resin is injected from the injection device 3 (see Figure 1) and filled into the parison molding cavity 52, a parison 62 is formed as shown in Figure 3C. The parison 62 consists of a main body 63 and a flange-shaped opening 64. The end face of the flange-shaped opening 64 is rounded on the opening side. Specifically, it is formed as a smooth annular projection 66. This is because the annular surface 48 is formed as a non-smooth recess. As will be explained later, a resin container is formed from the parison 62, and the annular projection 66 of the flange-shaped opening 64 maintains this shape. When a film-like lid is attached to the flange-shaped opening 64 after food or the like has been placed in the resin container, the presence of the annular projection 66 reduces the bonding area and increases adhesion. Furthermore, the small bonding area makes it easy to peel off the film-like lid, which is an excellent benefit.

[0024] The flange-shaped opening 64 of the parison 62 has an outer peripheral surface 67 formed as a cylindrical surface. This outer peripheral surface 67 is formed by the outer peripheral surface forming side wall surface 45 of the first annular step portion 44 of the injection molding die 38.

[0025] The mold clamping device 2 (see Figure 1) is driven to open the mold. As shown in Figure 3D, the injection molding die 38 and the intermediate mold 41 are opened. At this time, the parison 62 remains in the core 47 of the intermediate mold 41. The intermediate plate 10 (see Figures 1 and 2) is inverted to the second inversion position. As described above, the first intermediate mold group 34 and the blow molding die group 32 face each other. At this time, as shown in Figure 3E, the intermediate mold 41 with the parison 62 remaining faces the blow molding die 39.

[0026] The split molds 56, 56 are joined together and the mold is clamped. In the initial stage of this clamping, as shown in Figure 3F, the second annular step portion 58 of the blow molding die 39 contacts the flange-shaped opening portion 64 of the parison 62. At this time, the parting lines PL, PL are open by a gap 69. Further clamping closes the parting lines PL, PL completely, as shown in Figure 3G, and the flange-shaped opening portion 64 is compressed in the opening compression cavity 71, which consists of the second annular step portion 58 of the blow molding die 39 and the annular surface portion 48 of the intermediate die 41. The gap 69 (see Figure 3F) is formed first because the opening forming cavity 54 (see Figures 3B and 3C) has a slightly larger capacity than the opening compression cavity 71. The compression of the flange-shaped opening portion 64 prevents sink marks on the annular projection portion 66.

[0027] The operation of compressing the flange-shaped opening 64 will be explained in more detail. In the initial stage of mold clamping, as explained in Figure 3F, the parting lines PL, PL are open by a gap 69. Figure 4A shows a magnified view of the blow molding die 39, a part of the intermediate die 41, and a part of the parison 62. When the parting lines PL, PL are open by a gap 69, the back side 72 of the flange-shaped opening 64 of the parison 62 comes into contact with the second annular step 58. This generates resin pressure in the part indicated by reference numeral 70.

[0028] If the mold is further clamped in this state, the area indicated by reference numeral 70 expands, and the resin pressure in the area indicated by reference numeral 73 temporarily increases, as shown in Figure 4B. This is because the resin is compressible, and the resin pressure increases instantaneously and locally. In contrast, the rise in resin pressure is slightly delayed near the parting line PL, which is spaced apart from the back surface 72 of the flange-shaped opening 64. Therefore, resin leakage from the parting line PL can be prevented. In other words, the generation of burrs can be prevented. The reason why the generation of burrs at the flange-shaped opening 64 can be prevented in this way is that the second annular step portion 58 of the blow molding die 39 has an outer peripheral contact side wall surface 60 that is connected to the parting line PL. This is because the outer peripheral contact side wall surface 60 can slightly delay the rise in resin pressure near the parting line PL.

[0029] Furthermore, immediately after mold clamping is complete, the resin pressure becomes uniform within the flange-shaped opening 64. In other words, localized unevenness in resin pressure is eliminated. As mentioned above, the flange-shaped opening 64 is compressed, so shrinkage in this area is prevented.

[0030] Once the mold clamping is complete, compressed air is supplied from the compressed air supply device 5 (see Figure 1). As shown in Figure 3H, compressed air is supplied from the compressed air holes 50, 50, causing the main body 63 of the parison 62 to expand. In other words, blow molding is performed. A resin container 74 with a flange-shaped opening 64 is formed. As shown in Figure 3I, the split molds 56, 56 are opened in the blow molding mold 39. Then the mold is opened. This yields the resin container 74.

[0031] As can be seen from Figures 1 and 2, when the intermediate platen 10 is placed in the second inversion position and clamped, the first intermediate mold group 34 and the blow molding mold group 32 are clamped, but at the same time, the injection molding mold group 31 and the second intermediate mold group 35 are also clamped. In other words, as explained in Figures 3F, 3G, and 3H, the intermediate mold 41 of the first intermediate mold group 34 and the blow molding mold 39 are clamped, but at this time, the injection molding mold group 31 and the second intermediate mold group 35 are also clamped. That is, as shown in Figure 3B, the injection molding mold 38 and the intermediate mold 41 of the second intermediate mold group 35 are also clamped. In this way, when blow molding is performed in the first intermediate mold group 34 and the blow molding mold group 32, injection molding can be performed in the injection molding mold group 31 and the second intermediate mold group 35.

[0032] <Comparative Example> While the molding die 30 according to the first embodiment can effectively prevent burrs, a comparative example molding die that is prone to burr formation will be described. A part of the molding die 101 according to the comparative example is shown in Figure 5A. This molding die 101 is also a mold for carrying out the injection blow molding method and is designed to mold a resin container with a flange-shaped opening. It is used by being attached to the injection blow molding machine 1 shown in Figure 1. Furthermore, the molding die 101 according to the comparative example is similar in structure to the molding die 30 according to the first embodiment (Figures 3A and 3E), except that the position of the parting lines PL and PL are different.

[0033] Figure 5A shows parts of the intermediate mold 102 and the blow molding mold 103 that constitute the molding die 101. Compared to the molding die 30 of the first embodiment shown in Figure 4A, it can be seen that the positions of the parting lines PL and PL are different. In other words, the blow molding mold 103 also has a second annular step portion 105, but this second annular step portion 105 is directly connected to the parting line PL. The outer peripheral contact side wall surface 60 that is provided in the blow molding mold 39 of the molding die 30 of the first embodiment shown in Figure 4A is absent. As shown in Figure 5A, the outer peripheral surface 109 of the flange-shaped opening portion 108 of the parison 107 is formed by the intermediate mold 102.

[0034] With the parison 107 remaining in the intermediate mold 102 according to the comparative example, the blow molding mold 103 and the intermediate mold 102 are clamped together. As shown in Figure 5A, when the second annular step portion 105 contacts the back side 110 of the flange-shaped opening portion 108, the parting lines PL, PL are open. Initially, the resin pressure increases on the back side 110 of the flange-shaped opening portion 108, as indicated by reference numeral 112. As the clamping continues, the parting lines PL, PL narrow, as shown in Figure 5B. The area of ​​high resin pressure expands near the parting lines PL, PL, as indicated by reference numeral 113. Therefore, as indicated by reference numeral 114, the resin under high pressure leaks out from the gap between the parting lines PL, PL. In other words, burrs are generated.

[0035] The reason why burrs are more likely to form in the molding die 101 of the comparative example is that the outer peripheral contact side wall surface 60, which is present in the blow molding die 39 of the molding die 30 (see Figure 4A) according to the first embodiment, is absent. In the molding die 30 according to the first embodiment, the outer peripheral contact side wall surface 60 is connected to the parting line PL, which delays the resin pressure rising due to the compression of the flange-shaped opening 64 from reaching the vicinity of the parting line PL.

[0036] [Second Embodiment] A second embodiment will now be described. The injection molding machine 1 according to the second embodiment is configured in the same way as the injection molding machine 1 described in Figure 1, so the description of the injection molding machine 1 will be omitted. In the second embodiment, the molding die 30A differs in configuration from the molding die 30 according to the first embodiment, but the only difference is the shape of the first annular step portion 44 of the injection molding die 38 (see Figure 3A). In other words, in the second embodiment as well, as shown in Figure 2, it is composed of an injection molding die group 31, first and second intermediate die groups 34 and 35, and a blow molding die group 32, so the explanation of this point will also be omitted.

[0037] Figure 6A shows the injection molding die 38A and a portion of the intermediate mold 41 of the molding die 30A according to the second embodiment. The difference from the molding die 30 according to the first embodiment (Figure 3B) is the shape of the first annular step portion 44A. In the second embodiment, multiple radial grooves 75, ... are formed in the first annular step portion 44A. This is a difference from the first embodiment. The intermediate mold 41 and the blow molding die 39 (see Figure 3E) are configured in the same way as in the first embodiment, so their description is omitted.

[0038] The injection molding method in the second embodiment is substantially the same as the injection molding method in the first embodiment, as described in Figures 3A to 3I, and Figures 4A and 4B. Therefore, only the differences between the injection molding method in the second embodiment and the first embodiment will be described.

[0039] When the injection molding die 38A and the intermediate mold 41 of the molding die 30A according to the second embodiment are clamped together and injection is performed, a parison 62A as shown in Figure 6B is formed. Figure 6B is a side view of the parison 62A as seen from the main body portion 63 side. Multiple striated protrusions 77, 77, ... are formed on the flange-shaped opening portion 64A of the parison 62A. These striated protrusions 77, 77, ... are formed by grooves 75, ... of the first annular step portion 44A.

[0040] Figure 6C shows a cross-sectional view of the striate projection 77 cut at the XX cross-section in Figure 6B. The striate projections 77, 77, ... have a trapezoidal cross-section. In other words, the cross-section of the striate projections 77, 77, ... is narrower in the height direction. The striate projections 77, 77, ... are formed in this way because the grooves 75, 75, ... (see Figure 6A) are narrower in the depth direction.

[0041] Because these ridged protrusions 77, 77, ... are formed on the flange-shaped opening 64A of the parison 62A, the volume of the flange-shaped opening 64A is larger than that of the opening compression cavity 71 (see Figure 3G). In other words, as shown in Figure 3G, when the intermediate mold 41 and the blow molding mold 39 are clamped together, the flange-shaped opening 64A is compressed by the volume of these ridged protrusions 77, 77, ...

[0042] [Second Embodiment: Modified Version] The molding die 30A (see Figure 6A) according to the second embodiment can be deformed. Specifically, the shape of the groove 75 can be deformed. Figures 6D and 6E show cross-sections of the ridged projections 77' and 77'' of the flange-shaped openings 64A' and 64A'' of the parisons 62A' and 62A'' formed by the deformed molding die 30A, respectively. The ridged projection 77' shown in Figure 6D has a semi-circular cross-section, while the ridged projection 77'' shown in Figure 6E has a triangular cross-section. In both modified examples, the width of the ridged projections 77' and 77'' is narrower at the top.

[0043] [Other variations] The first and second embodiments can be modified in various ways. For example, the molding die 30 (see Figure 4A) according to the first embodiment can be modified. Figure 7 shows a molding die 30B comprising an intermediate die 41B according to a modified example and a blow molding die 39. In the intermediate die 41B according to the modified example, the annular surface portion 48B is formed in a planar shape. Therefore, the flange-shaped opening portion 64B of the formed parison 62B has a planar end face 80 on the opening side. In the resin container formed by blow molding from this parison 62B, the end face 80 on the opening side of the flange-shaped opening portion 64B is planar, so the adhesion area of ​​the film-like lid is increased.

[0044] The first and second embodiments can be further modified. As explained in Figure 2, the injection molding die group 31 is described as being composed of two or more injection molding dies 38, 38, ... Similarly, the blow molding die group 32 is described as being composed of the same number of blow molding dies 39, 39, ... and the first and second intermediate die groups 34 and 35 are described as being composed of the same number of intermediate dies 41, 41, ... However, the injection molding die group 31 may be composed of one injection molding die 38, the blow molding die group 32 may be composed of one blow molding die 39, and the first and second intermediate die groups 34 and 35 may each be composed of one intermediate die 41, 41.

[0045] The present invention has been described in detail above based on embodiments, but it goes without saying that the present invention is not limited to the embodiments already described, and various modifications are possible without departing from the spirit of the invention. The multiple examples described above can also be implemented in combination as appropriate. [Explanation of Symbols]

[0046] 1 Injection blow molding machine 2 Mold clamping device 3. Injection device 4. Controller 5 Compressed air supply device 7 Fixed plate 8. Movable plate 9. Clamping housing 10 Intermediate section 11 Tie bar 13 Toggle mechanism 15 Intermediate plate support 16 Intermediate panel body 17 Intermediate panel opening / closing mechanism 19 Heating cylinder 20 Screw 22 Drive mechanism 23 Hopper 24 Injection nozzle 30 Molding die 31 Injection molding die group 32 Blow molding die group 34 First intermediate mold group 35 Second intermediate mold group 38 Injection molding dies 39 Blow molding dies 41 Intermediate mold 43 First recess 44 First annular step portion 45 Side wall surface for forming the outer circumferential surface 46 Runner 47 Core 48 Annular surface portion 50 Compression air hole 52 parison molding cavities 53 Cavity for forming the main body 54 Cavity for forming the opening 56 Split type 57 Second recess 58 Second annular step portion 60 Side wall surface for contact with the outer circumferential surface 62 Parison 63 Main body 64 Flange-shaped opening 66 Annular projection 67 Outer surface 69 Gap 71 Cavity for compression of opening 72 Back side 75 groove 77 striation

Claims

1. An injection molding die comprising a first recess and a first annular stepped portion which is an annular stepped portion formed around the first recess, A blow molding die consisting of multiple segmented parts, which, when joined together, form a second recess and a second annular step, which is an annular step; It consists of an intermediate mold comprising a core with compressed air holes formed inside and an annular surface portion which is an annular surface formed around the core, When the injection molding die and the intermediate mold are clamped together, a cavity for forming the main body portion of the parison is formed from the first recess and the core, and a cavity for forming the flange-shaped opening portion of the parison is formed from the first annular step portion and the annular surface portion. When the blow molding die and the intermediate die are clamped together, a mouth compression cavity is formed that compresses the flange-shaped mouth of the parison from the former second annular step portion and the annular surface portion. The cavity for forming the opening has a larger volume compared to the cavity for compressing the opening. The first annular step portion is provided with an outer surface forming side wall surface for forming the outer surface of the flange-shaped opening of the parison, and the outer surface forming side wall surface is connected to the parting line. The second annular step portion is provided with an outer surface contact side wall surface that contacts the outer surface of the flange-shaped opening of the parison, and the outer surface contact side wall surface is connected to a parting line, in a mold for molding a resin container.

2. The mold for molding a resin container according to claim 1, wherein an annular groove consisting of a smooth concave curved surface is formed on the annular surface portion, and a gentle annular projection is formed on the opening end face of the flange-shaped mouth portion of the parison.

3. The molding die for a resin container according to claim 1 or 2, wherein the first annular step portion is formed to be uniformly deeper than the second annular step portion, and the volume of the cavity for forming the mouth is larger than that of the cavity for compressing the mouth.

4. The mold for molding a resin container according to claim 1 or 2, wherein the first annular step portion has a recess formed in at least a part of it compared to the second annular step portion, and the volume of the cavity for forming the mouth is larger than that of the cavity for compressing the mouth due to the recess.

5. A mold for molding a resin container according to claim 1 or 2, wherein a plurality of radial grooves are formed in the first annular step portion, and a plurality of radial ridge-like projections are formed in the flange-like opening portion of the parison, and the volume of the opening-forming cavity is larger than that of the opening-compression cavity by the amount of the ridge-like projections.

6. The mold for molding a resin container according to claim 5, wherein the groove narrows in the depth direction of the groove, and the cross-section of the striated projection of the parison narrows in the height direction of the striated projection.

7. The mold for molding a resin container according to claim 6, wherein the groove has a triangular cross-sectional shape, and the cross-section of the striated projection of the parison is formed to be triangular.

8. The blow molding die is a mold for molding a resin container according to claim 1 or 2, comprising two split molds in a two-part shape.

9. A group of injection molding dies, A group of blow molding dies, It consists of a group of reversible intermediate molds, The injection molding die group consists of a plurality of injection molding dies, The blow molding die group consists of the same number of blow molding dies as the injection molding dies, The aforementioned intermediate mold group consists of a first intermediate mold group and a second intermediate mold group arranged back-to-back with each other, and both the first and second intermediate mold groups are composed of the same number of intermediate molds as the injection molding molds. When the intermediate mold group is placed in the first inversion position and clamped, the injection molding mold of the injection molding mold group and the intermediate mold of the first intermediate mold group are clamped together, and the intermediate mold of the second intermediate mold group and the blow molding mold group of the blow molding mold group are clamped together. A mold for molding a resin container according to claim 1 or 2, wherein when the intermediate mold group is placed in a second inversion position and the mold is clamped, the injection molding mold of the injection molding mold group and the intermediate mold of the second intermediate mold group, and the intermediate mold of the first intermediate mold group and the blow molding mold of the blow molding mold group are clamped, respectively.

10. Clamping device and An injection device for injecting resin, The mold provided in the clamping device, It consists of a compressed air supply device that supplies compressed air to the mold, The clamping device consists of a fixed plate and A movable plate that is opened and closed by a clamping mechanism, It consists of an intermediate plate that is reversibly provided between the fixed plate and the movable plate, The mold is provided on the fixed platen and comprises an injection molding mold group consisting of at least one injection molding mold, A group of blow molding dies provided on the movable platen, consisting of the same number of blow molding dies as the injection molding dies, A first group of intermediate molds is provided on one side of the aforementioned intermediate plate and consists of the same number of intermediate molds as the injection molding molds, It consists of a second group of intermediate molds provided on the other side of the aforementioned intermediate plate and comprising the same number of intermediate molds as the injection molding mold, The injection molding die comprises a first recess and a first annular stepped portion which is an annular stepped portion formed around the first recess. The blow molding die consists of a plurality of segmented dies, and when joined together, a second recess and a second annular step are formed. The aforementioned intermediate mold comprises a core with compressed air holes formed inside and an annular surface portion which is an annular surface formed around the core. When the intermediate plate is placed in the first inversion position and the mold clamping device is clamped, the injection molding dies of the injection molding die group, the intermediate dies of the first intermediate mold group, the intermediate dies of the second intermediate mold group, and the blow molding dies of the blow molding die group are each clamped together. When the intermediate plate is placed in the second inversion position and the mold clamping device is clamped, the injection molding dies of the injection molding die group, the intermediate dies of the second intermediate mold group, the intermediate dies of the first intermediate mold group, and the blow molding dies of the blow molding die group are all clamped together. When the injection molding die and the intermediate mold are clamped together, a body-forming cavity is formed from the first recess and the core to form the main body of the parison, and a mouth-forming cavity is formed from the first annular step and the annular surface to form the flange-shaped mouth of the parison. When the blow molding die and the intermediate die are clamped together, a mouth compression cavity is formed from the second annular step portion and the annular surface portion to compress the flange-shaped mouth portion of the parison. The cavity for forming the opening has a larger volume compared to the cavity for compressing the opening. The first annular step portion is provided with an outer surface forming side wall surface for forming the outer surface of the flange-shaped opening of the parison, and the outer surface forming side wall surface is connected to the parting line. The second annular step portion is provided with an outer surface contact side wall surface that contacts the outer surface of the flange-shaped opening portion of the parison, and the outer surface contact side wall surface is connected to a parting line, in an injection blow molding machine for molding resin containers.

11. An injection blow molding machine for molding resin containers according to claim 10, wherein an annular groove consisting of a smooth concave curved surface is formed on the annular surface portion, and a gentle annular projection is formed on the opening end face of the flange-shaped mouth portion of the parison.

12. The injection blow molding machine for molding resin containers according to claim 10 or 11, wherein the first annular step portion is formed to be uniformly deeper than the second annular step portion, and the volume of the cavity for forming the mouth is larger than that of the cavity for compressing the mouth.

13. The injection blow molding machine for molding resin containers according to claim 10 or 11, wherein the first annular step portion has a recess formed in at least a part of it compared to the second annular step portion, and the volume of the mouth-forming cavity is larger than that of the mouth-compression cavity due to the recess.

14. The injection blow molding machine for molding resin containers according to claim 10 or 11, wherein a plurality of radial grooves are formed in the first annular step portion, and a plurality of radial ridge-like projections are formed in the flange-like opening portion of the parison, and the volume of the opening-forming cavity is larger than that of the opening-compression cavity by the amount of the ridge-like projections.

15. The injection blow molding machine for molding resin containers according to claim 14, wherein the groove narrows in the depth direction of the groove, and the cross-section of the striated projection of the parison narrows in the height direction of the striated projection.

16. The injection blow molding machine for molding resin containers according to claim 15, wherein the groove has a triangular cross-sectional shape, and the cross-section of the striated projection of the parison is formed to be triangular.

17. The blow molding die consists of two split dies, as described in claim 10 or 11, for injection blow molding of resin containers.

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