JP2017087651A - Preform, die, production device and production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a preform, a die, a production device and a production method capable of producing a resin product with a double wall structure.SOLUTION: Provided is a preform 10 made of a resin for blow molding, comprising: a cylindrical barrel part 12 including a mouth part 12a and the first bottom part 12b; and a planar outer circumferential part 13 formed so as to surround the outer circumference of the barrel part 12, having the second bottom part 14 in which the inner wall face of the outer circumferential part 13 and the outer wall face of the barrel part 12 are continuously formed, and a space 15 is formed by the second bottom part 14, the inner wall face of the outer circumferential part 13, and the outer wall face of the barrel part 12.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a preform, a mold, a manufacturing apparatus, and a manufacturing method for manufacturing a product having a double wall structure.

  Conventionally, as a product having a double wall structure, there are a glass bulb cover, a beverage container, and the like. In addition, there is a need to manufacture a product having a double wall structure with a resin because of cost reduction. For example, a device for injection molding a resin light bulb cover is disclosed in Patent Document 1 below.

JP 58-92538 A

  However, the conventional injection molding apparatus including the apparatus described in Patent Document 1 cannot manufacture a preform or product having a double wall structure.

  Then, an object of this invention is to provide the preform, metal mold | die, manufacturing apparatus, and manufacturing method which can manufacture the product made from resin which has a double wall structure.

In order to achieve the above object, the preform of the present invention comprises:
A resin preform for blow molding,
A cylindrical trunk having a mouth and a first bottom;
A plate-shaped outer peripheral portion formed so as to surround the outer periphery of the trunk portion;
With
Having a second bottom portion formed continuously with an inner wall surface of the outer peripheral portion and an outer wall surface of the trunk portion;
A space is formed by the second bottom portion, the inner wall surface of the outer peripheral portion, and the outer wall surface of the trunk portion.

  According to this structure, the resin product of a double wall structure can be manufactured by blow-molding the space formed by the second bottom portion, the inner wall surface of the outer peripheral portion, and the outer wall surface of the trunk portion.

In the preform of the present invention,
It is preferable that the said outer peripheral part and the said trunk | drum are continuing in the peripheral part of the mouth part of the said trunk | drum.

  According to this structure, since the outer peripheral part is formed continuously from the peripheral part of the mouth part of the trunk part, in the resin product after blow molding, the boundary between the trunk part and the outer peripheral part can be made inconspicuous. .

The mold of the present invention is
A core mold having a rod-shaped protrusion, and
A first cavity mold having a cylindrical body forming part that forms a first gap for forming a preform body part between the outer peripheral surface of the projection part,
A second cavity mold having an outer peripheral portion forming portion for forming a second gap for forming an outer peripheral portion disposed on an outer peripheral side of the trunk portion of the preform between the outer peripheral surface of the trunk portion forming portion. When,
A liner mold for pouring resin into the first gap;
With
In a state where the core mold, the first cavity mold, and the second cavity mold are combined with each other, the first gap and the second gap are continuous.

  According to this configuration, a preform that can be blow-molded by blowing blow air between the body portion and the outer peripheral portion of the preform can be manufactured.

In the mold of the present invention,
It is preferable that a concave portion is formed in the protruding portion of the core mold.

  According to this configuration, when the preform manufactured in a state of being bonded to the core mold protrusion is transported, the preform is difficult to drop from the core mold.

The mold of the present invention is
A first blow mold for directing blow air between the barrel and the outer periphery;
A second blow mold having an inner wall surface that comes into contact with the outer peripheral surface of the outer peripheral portion swelled by the blow air.

  According to this configuration, a resin product having a double wall structure can be manufactured at low cost without separately preparing a part for the body part and a part for the outer peripheral part.

The injection blow molding apparatus of the present invention is
An injection device for manufacturing the preform;
A blow molding device that blow-molds blow air between the body portion and the outer peripheral portion of the preform.

  According to this configuration, a resin product having a double wall structure can be manufactured at low cost without separately preparing a part for the body part and a part for the outer peripheral part.

Moreover, the production method of the present invention comprises:
A method for producing a resin product having a double wall structure,
A step of producing the above preform;
And blow molding blow air between the body portion and the outer peripheral portion of the preform.

  According to this configuration, compared with a manufacturing method in which a part for a body part and a part for an outer periphery part are separately prepared and both parts are joined, a resin product having a double wall structure is manufactured at a simple and low cost. can do.

  ADVANTAGE OF THE INVENTION According to this invention, the preform, metal mold | die, manufacturing apparatus, and manufacturing method which can manufacture the product made from resin which has a double wall structure can be provided.

(A) is a perspective view of a resin product having a double wall structure, (b) is a plan view of the resin product, (c) is a front view of the resin product, and (d) is a bottom view of the resin product. It is sectional drawing in the AA of FIG.1 (b). (A) is a perspective view of a preform according to the present invention, (b) is a plan view of the preform, (c) is a sectional view taken along line BB in (b), and (d) is a bottom view of the preform. is there. It is sectional drawing which shows the modification of a preform. 1 is a block diagram of an injection blow molding apparatus according to the present invention. It is a figure explaining the structure of the injection apparatus in an injection blow molding apparatus. (A) is a figure explaining the structure of the injection apparatus in an injection blow molding apparatus, (b) is the elements on larger scale of (a). (A) is a figure explaining the structure of the blow molding apparatus in an injection blow molding apparatus, (b) is the elements on larger scale of (a). It is a figure explaining the structure of the blow molding apparatus in an injection blow molding apparatus. It is a flowchart which shows the manufacture procedure of a resin product.

Hereinafter, an example of this embodiment will be described with reference to the drawings.
1 and 2 show a resin product 1 manufactured by a manufacturing apparatus and a manufacturing method according to the present invention. The resin product 1 is formed of a resin material such as polycarbonate, and can be used as, for example, a light bulb cover or a beverage container. The resin product 1 has a double wall structure constituted by an inner wall 2 formed in a cylindrical shape and an outer wall 3 formed in a spherical shape.

  The inner wall 2 is formed so as to penetrate the central portion of the resin product 1, and has an opening 2 a at one end and an opening 2 b at the end opposite to the opening 2 a. The outer wall 3 is formed so as to surround the outer periphery of the inner wall 2, and has an opening 3a that is continuous with the peripheral edge 2c of the opening 2a on the opening 2a side of the inner wall 2 and larger than the opening 2b on the opening 2b side of the inner wall 2. doing. For example, when the resin product 1 is used as a light bulb cover, the light bulb is disposed in the space 4 in the inner wall 2.

  FIG. 3 shows a preform 10 for forming the resin product 1. The preform 10 is formed of a resin material as in the case of the resin product 1 and includes a barrel portion 12 formed in a cylindrical shape and an outer peripheral portion 13 formed in a plate shape. The trunk portion 12 of this example is formed in a cylindrical shape.

  The trunk | drum 12 has the opening part 12a in one edge part, and has the bottom part 12b in the edge part on the opposite side to the opening part 12a.

  The outer peripheral portion 13 has a skirt-like shape and is formed so as to surround the outer periphery of the trunk portion 12. The outer peripheral portion 13 is formed continuously with the peripheral edge portion 12 c of the mouth portion 12 a on the mouth portion 12 a side of the trunk portion 12. 12 is formed so as to have an opening 13a around the trunk portion 12 on the bottom 12b side. The outer peripheral portion 13 is formed to increase in diameter as it approaches the bottom portion 12 b from the mouth portion 12 a of the trunk portion 12. A minute flange portion 13b is formed around the opening 13a.

  By forming the outer peripheral portion 13 and the trunk portion 12 continuously, an inner wall surface of the outer peripheral portion 13 and an outer wall surface of the trunk portion 12 are continuously formed between the outer peripheral portion 13 and the trunk portion 12. A bottom 14 is provided. Thus, a space 15 is formed on the outer side of the body portion 12 by the bottom portion 14, the inner wall surface of the outer peripheral portion 13, and the outer wall surface of the body portion 12.

  The resin product 1 is formed by blowing blow air into the space 15 of the preform 10 to blow-mold the outer peripheral portion 13.

  The form of the preform 10 is not limited to that shown in FIG. 3. For example, as shown in FIG. 4, the outer peripheral portion 13 is continuous with the outer wall of the trunk portion 12 at a midway portion slightly away from the mouth portion 12 a of the trunk portion 12. However, it may be formed so as to surround a part of the outer periphery of the body portion 12.

  Next, an injection blow molding apparatus for forming the preform 10 and the resin product 1 will be described with reference to FIGS.

  As shown in FIG. 5, the injection blow molding apparatus 20 includes an injection apparatus 30 for manufacturing the preform 10 and a blow molding apparatus 70 for blowing the preform 10 to manufacture the resin product 1. Yes. The injection apparatus 30 includes an injection molding unit 31 that injection-molds the preform 10 and a resin supply unit 32 that supplies a resin material that is a raw material to the injection molding unit 31. The injection device 30 and the blow molding device 70 are provided at positions rotated around the conveying means 90 in a range of 90 ° to 180 °, for example. In addition, you may provide the temperature control apparatus for adjusting the temperature of the preform 10 between the injection apparatus 30 and the blow molding apparatus 70 as needed. Further, a take-out unit for taking out the blow-molded product may be provided at the subsequent stage of the blow-molding apparatus 70.

  As shown in FIGS. 6 and 7, the injection molding unit 31 of the injection device 30 includes a runner mold 45 provided on the machine base 41, a first cavity mold 50 provided on the runner mold 45, A second cavity mold 55 and a core mold 60 provided on the cavity mold 50 are provided. The upper end of the core mold 60 is attached to the conveying means 90. Inside the first cavity mold 50, the second cavity mold 55, and the core mold 60, a fluid circulation circuit (not shown) in which a fluid for cooling or temperature adjustment processing circulates is provided. The temperature of the fluid is set according to the cooling strength required for each of the first cavity mold 50, the second cavity mold 55, and the core mold 60.

  The core mold 60 defines the inner peripheral surface of the body portion 12 in the preform 10. The core mold 60 is provided with a rod-shaped protrusion 61 that defines the inner peripheral surface of the body 12. A recess 62 is formed on the outer wall of the protrusion 61 as shown in FIG. 7B (illustration of the preform 10 is omitted in FIG. 7B). The concave portion 62 may be, for example, a dot shape, or may have a predetermined width along the outer peripheral direction of the protruding portion 61. Moreover, the number of the recessed parts 62 formed may be single or plural.

  The first cavity mold 50 defines an outer peripheral surface of the body portion 12 and an inner peripheral surface of the outer peripheral portion 13 in the preform 10. The first cavity mold 50 is provided with a cylindrical body part forming part 51 for forming the body part 12 of the preform 10. A side surface on the inner side of the trunk portion forming portion 51 forms a first gap 52 for forming the trunk portion 12 of the preform 10 between the outer peripheral surface of the projection portion 61 in the core mold 60. The first cavity mold 50 has an accommodation hole 58 in which the second cavity mold 55 is accommodated. The accommodation hole 58 is tapered, and the inner wall surface is an inclined surface 58a. The first cavity mold 50 has an inclined hole 59 extending from the upper surface thereof downward along the inclined direction of the inclined surface 58a.

  The second cavity mold 55 is composed of a pair of cavity split molds 55 </ b> A and 55 </ b> B, and defines the outer peripheral surface of the outer peripheral portion 13 disposed on the outer peripheral side of the body portion 12 of the preform 10. The second cavity mold 55 is provided with an outer peripheral portion forming portion 56 for forming the outer peripheral portion 13 of the preform 10. An inner side surface 56 a of the outer peripheral portion forming portion 56 forms a second gap 57 for forming the outer peripheral portion 13 of the preform 10 between the outer peripheral surface of the body portion forming portion 51 in the first cavity mold 50. .

  The outer side surface 56 b of the outer peripheral portion forming portion 56 is inclined in the same direction as the inclined surface 58 a of the accommodation hole 58. An inclined pin 101 is fixed to the flange portion 100 of the second cavity mold 55 with an elastic member 102 (compression spring or the like) interposed therebetween. The inclined pin 101 can enter the inclined hole 59 with the elastic member 102 interposed. Since the inclined pin 101 and the inclined hole 59 function as a guide mechanism, the second cavity mold 55 is configured to be movable up and down with respect to the first cavity mold 50.

  The injection device 30 is configured such that the first gap 52 and the second gap 57 are continuous gaps in a state where the core mold 60, the first cavity mold 50, and the second cavity mold 55 are combined with each other. ing.

  The runner mold 45 is connected to the resin supply unit 32, and introduces resin, which is a raw material of the preform 10, into the first gap 52 of the first cavity mold 50 through the resin supply unit 32. In this example, the resin material is introduced into the first gap 52 from the gate 53 provided at the bottom center of the first cavity mold 50, but the present invention is not limited to this. For example, the gate is directly connected to the second gap 57. Then, the resin material may be introduced into the second gap 57.

  The resin material introduced from the resin supply unit 32 is poured from the first gap 52 into the second gap 57 to form the preform 10. In addition, the metal mold | die used for forming the preform 10 should just be a metal mold | die which can form the preform which has the trunk | drum and the outer peripheral part integrally, and is not limited to the structure of this example. .

  The conveying means 90 conveys the preform 10 injection-molded by the injection device 30 from the injection device 30 to the blow molding device 70 in a state where the preform 10 is held by the protrusion 61 of the core mold 60. In this example, the preform 10 held by the core mold 60 is conveyed from the injection device 30 to the blow molding device 70 by rotating the conveying means 90 by 180 ° (see FIG. 5). The injection-molded preform 10 is held by the core mold 60 in a state in which a part of the body 12 of the preform 10 enters the recess 62 of the projection 61 (see FIG. 8B).

  As shown in FIGS. 8A and 9, the blow molding device 70 includes a first blow mold 75 and a second blow mold 80 that are combined with the core mold 60.

  The second blow mold 80 is composed of a pair of blow split molds 80 </ b> A and 80 </ b> B and defines the outer peripheral surface of the outer wall 3 in the resin product 1. The second blow mold 80 is provided with an inner wall surface 81 for forming the outer wall 3 of the resin product 1, that is, an inner wall surface 81 that comes into contact with the outer peripheral surface of the outer peripheral portion 13 of the preform 10 swelled by blow air. . The second blow mold 80 is assembled to the core mold 60 so that the inner wall surface 81 surrounds the outer periphery of the outer peripheral portion 13 of the preform 10. Inside the second blow mold 80, a cooling circuit (not shown) for circulating a cooling medium is provided.

  The first blow mold 75 supplies blow air to the preform 10. The first blow mold 75 is provided with an air flow path 76, and blow air is supplied to the preform 10 through the air flow path 76. The first blow mold 75 is provided with a cylindrical projection 77 that defines the end of the air flow path 76. The first blow mold 75 is assembled to the core mold 60 so that the protrusion 77 enters the space 15 of the preform 10. The assembled first blow mold 75 sandwiches the end portion of the outer peripheral portion 13 of the preform 10 between the outer peripheral surface of the protrusion 77 and the inner wall surface 81 of the second blow die 80. Further, an air outlet port 78 is formed between the inner peripheral surface of the protrusion 77 and the outer peripheral surface of the body 12 of the preform 10.

  Blow air supplied from the air flow path 76 is introduced into the space 15 of the preform 10 through the air outlet 78. The outer peripheral portion 13 of the preform 10 is blown by the introduced blow air, and the outer wall 3 of the resin product 1 is blow-molded.

Next, based on FIG. 10, the manufacturing method of the resin product 1 which has a double wall structure is demonstrated.
In the injection device 30, the second cavity molds (cavity split molds) 55A and 55B and the core mold 60 are clamped with respect to the first cavity mold 50 assembled on the runner mold 45 (see step S101, FIG. 6). ).

  A resin material is introduced into the first gap 52 from the resin supply part 32 of the runner mold 45 through the gate 32 of the first cavity mold 50 (see FIG. 6). The introduced resin material flows from the first gap 52 into the second gap 57 continuous to the first gap 52, thereby forming the preform 10 (step S102).

  After the injection molding of the preform 10 is completed, the first cavity mold 50, the second cavity mold 55, and the core mold 60 are opened (step S103). In the mold opening, the core mold 60 is raised by the conveying means 90 (see arrow A in FIG. 7). As the core mold 60 is raised, the second cavity 55 slides obliquely upward with respect to the first cavity 50 by a guide mechanism constituted by the inclined pin 101 and the inclined hole 59. (See arrows B and C in FIG. 7). Further, at the time of step S103, the preform 10 is held by the protrusion 61. Since the distance between the cavity split dies 55A and 55B increases after the mold is opened, the outer peripheral portion 13 of the undercut preform 10 does not interfere with the second cavity and is pulled upward while being held by the protrusion 61. .

  After opening the mold, the preform 10 held by the protrusion 61 of the core mold 60 is conveyed to the blow molding apparatus 70 by the conveying means 90 (step S104).

  Subsequently, in the blow molding apparatus 70, the first blow mold 75 and the second blow molds (blow split molds) 80A and 80B are clamped to the core mold 60 that has been conveyed (see step S105, FIG. 9). ). For mold clamping, the first blow mold 75 is raised toward the protrusion 61 of the core mold 60 by mold clamping means (not shown) (see arrow D in FIG. 8), and the blow split molds 80A and 80B are core molds. The projections 61 of 60 are brought closer from the left and right directions (see arrows E and F in FIG. 8). As a result, the projection 77 of the first blow mold 75 enters the space 15 of the preform 10, and the inner wall surface 81 of the blow split molds 80 </ b> A and 80 </ b> B surrounds the outer peripheral portion 13 of the preform 10.

  Blow air is supplied from the air flow path 76 of the first blow mold 75, and the blow air is introduced into the space 15 of the preform 10 through the air outlet port 78. The outer peripheral portion 13 of the preform 10 is blown by the introduced blow air and swells so as to stick to the inner wall surface 81 of the second blow mold 80, thereby forming the outer wall 3 in the resin product 1 (step S106). In this example, the body 12 of the preform 10 is maintained without being blown while being held by the protrusion 61 of the core mold 60.

  After the blow molding of the preform 10 is completed, the first blow mold 75, the second blow mold 80, and the core mold 60 are opened (step S107).

  After the mold is opened, the blow-molded preform 10 held by the protrusion 61 of the core mold 60 is released and taken out from the injection blow molding apparatus 20 (step S108).

  Subsequently, the bottom portion 12b of the body portion 12 of the blow-molded preform 10 is cut off by a predetermined amount (see step S109, FIG. 2) to complete the manufacture of the resin product 1 (bulb cover) of this example. . Further, if the opening 13a including the flange 13b of the outer peripheral portion 13 is not necessary, a predetermined amount may be cut off. The cut portion includes a convex portion formed by the concave portion 62 of the core mold 60.

By the way, the blow molding method is generally used in the manufacture of a light bulb cover having a body size larger than the neck size. Of these, in the injection blow molding method, the preform molded in the injection molding unit is transported to the blow molding unit while being held in the injection core mold unit, and air is introduced into the preform from the injection core mold unit. A desired light bulb cover is manufactured by deforming into a shape.
In addition, there is a light bulb cover having an inner and outer double wall structure in which a hollow cylindrical wall (inner wall) is provided inside a substantially spherical outer envelope (outer wall) as one form of the light bulb cover. For example, the light of an LED bulb accommodated in the inner wall is radiated through the inner wall and the outer wall, and is used in a lighting apparatus that requires a more aesthetic appearance. Currently, a cover having a double-wall structure is formed using, for example, a glass material, and there is a demand for converting it into a resin. However, in the conventional injection blow molding method, a cylindrical inner wall portion and a spherical outer wall portion are separately formed in advance, and both portions must be joined to form a double wall structure.

  On the other hand, according to the preform 10 of the present embodiment, the outer peripheral portion 13 and the trunk portion 12 are continuously formed via the bottom portion 14. Therefore, a space 15 is formed on the outer side of the body portion 12 by the bottom portion 14, the inner wall surface of the outer peripheral portion 13, and the outer wall surface of the body portion 12. Accordingly, the bulb cover having a double wall structure having the cylindrical inner wall 2 and the spherical outer wall 3 surrounding the outer periphery of the inner wall 2 by blowing blow air into the space 15 and blow-molding the outer peripheral portion 13. Etc. can be produced.

  Moreover, since the trunk | drum 12 and the outer peripheral part 13 are continuously formed integrally through the bottom part 14, in the resin product 1 after carrying out the blow molding of the preform 10, in the resin | drug 1 and the outer peripheral part 13, The resin product 1 having an excellent aesthetic appearance can be obtained. Further, when the preform 10 is blow-molded, the body portion 12 is maintained in a state of being held by the projection portion 61 of the core mold 60, so that the inner wall 2 of the resin product 1 that transmits the light bulb has an equal thickness. In addition, the resin product 1 having an excellent aesthetic appearance can be obtained.

  Further, according to the mold of the injection device 30, a continuous gap is formed by the first gap 52 for forming the body portion 12 of the preform 10 and the second gap 57 for forming the outer peripheral portion 13 of the preform 10. Can be formed as For this reason, the preform 10 which can be blow-molded by blowing blow air in the space 15 formed between the trunk | drum 12 and the outer peripheral part 13 can be manufactured.

  Further, since the concave portion 62 is formed on the outer wall of the protruding portion 61 of the core mold 60, when the preform 10 manufactured in a state of being bonded to the protruding portion 61 in the injection device 30 is conveyed to the blow molding device 70. The preform 10 can be prevented from falling from the core mold 60.

  Further, according to the mold of the blow molding apparatus 70, the space 12 between the body portion 12 and the outer peripheral portion 13 of the preform 10 in which the body portion 12 and the outer peripheral portion 13 are continuously and integrally formed. Blow molding is possible. For this reason, it is not necessary to prepare the resin part for the trunk part (inner wall part) and the resin part for the outer peripheral part (outer wall part) separately. Therefore, a resin product having a double wall structure can be manufactured at a low cost.

  Moreover, according to the manufacturing method of the resin product 1 having a double wall structure, the preform 10 having the body portion 12 and the outer peripheral portion 13 which are integrally formed is blow-molded to perform the resin product 1 in one stage. Can be manufactured. For this reason, compared to a manufacturing method in which a resin part for the body part (inner wall part) and a resin part for the outer periphery part (outer wall part) are prepared separately and both parts are joined, it is simple and low in cost. A resin product 1 having a wall structure can be manufactured.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimension, numerical value, form, number, location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  For example, in the description of the above embodiment, an example of blow molding the space 15 of the preform 10 has been described, but the present invention is not limited to this example. The blow molding may be performed by introducing blow air not only into the space 15 of the preform 10 but also into the internal space of the body portion 12.

1: resin product, 2: inner wall, 3: outer wall, 2a, 2b, 3a: opening, 2c: peripheral edge, 4, 5: space, 10: preform, 12: trunk, 12a: mouth, 12b: bottom 12c: peripheral part, 13: outer peripheral part, 13a: opening, 13b: flange part, 14: bottom part, 15: space, 20: injection blow molding apparatus, 30: injection apparatus, 31: injection molding part, 32: resin supply Part, 45: runner type, 50: first cavity type, 51: body part forming part, 52: first gap, 53: gate, 55: second cavity type, 56: outer peripheral part forming part, 57: second gap , 60: core mold, 61: protrusion, 62: recess, 70: blow molding device, 75: first blow mold, 76: air flow path, 77: protrusion, 78: air outlet, 80: second blow Mold, 81: inner wall surface, 90: conveying means

Claims (7)

A resin preform for blow molding,
A cylindrical trunk having a mouth and a first bottom;
A plate-shaped outer peripheral portion formed so as to surround the outer periphery of the trunk portion;
With
Having a second bottom portion formed continuously with an inner wall surface of the outer peripheral portion and an outer wall surface of the trunk portion;
A space is formed by the second bottom portion, the inner wall surface of the outer peripheral portion, and the outer wall surface of the trunk portion.
preform. The outer peripheral portion and the trunk portion are continuous at the peripheral edge portion of the mouth portion of the trunk portion,
The preform according to claim 1. A core mold having a rod-shaped protrusion, and
A first cavity mold having a cylindrical body forming part that forms a first gap for forming a preform body part between the outer peripheral surface of the projection part,
A second cavity mold having an outer peripheral portion forming portion for forming a second gap for forming an outer peripheral portion disposed on an outer peripheral side of the trunk portion of the preform between the outer peripheral surface of the trunk portion forming portion. When,
Runner type for pouring resin into the first gap,
With
In a state where the core mold, the first cavity mold, and the second cavity mold are combined with each other, the first gap and the second gap are continuous.
Mold. A recess is formed in the protrusion of the core mold.
The mold according to claim 3. A first blow mold for directing blow air between the barrel and the outer periphery;
A second blow mold having an inner wall surface that comes into contact with the outer peripheral surface of the outer peripheral portion swelled by the blow air;
Comprising
The mold according to claim 3 or claim 4. An injection device for producing the preform according to claim 1 or 2,
A blow molding device that blow-molds blow air between the body portion and the outer peripheral portion of the preform;
Comprising
Injection blow molding equipment. A method for producing a resin product having a double wall structure,
Producing the preform according to claim 1 or 2,
A step of blow-molding blow air between the body portion and the outer peripheral portion of the preform;
Manufacturing method.

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