Molding method of self-supporting resin container and primary molded body of self-supporting resin container

Abstract

To provide a blow molding method suitable for manufacturing a self-supporting resin container having a skirt part for self-supporting having been integrally formed in a state of surrounding a convex bottom part and a self-supporting resin container molded by using the molding method.SOLUTION: In a self-supporting resin container 1, blow molding is applied to a body part 14 in a state that a port part 13 and a skirt part 16 of a primary molded body 10 which is a resin-made injection molded body are being held, the port part and the skirt part are allowed to remain as a container port part 3 and a container skirt part 6 as they are, and a part between these is molded as a large-diameter container body part 4. The self-supporting resin container 1 having a complex sectional form where a cylindrical container skirt part 6 is integrally formed in a state of surrounding a convex bottom part 5a that seals a bottom edge of the large-diameter container body part 4 can be manufactured by blow molding.SELECTED DRAWING: Figure 1C

Description

[Technical field]

[0001] The present invention relates to a molding method for a free-standing resin container in which a skirt portion for supporting the container is integrally formed at the lower end of a cylindrical container body having a convex bottom such as a round bottom or a conical bottom so as to surround the convex bottom, a free-standing resin container obtained by the molding method, and a primary molded body which is an injection-molded resin product used to mold the resin container. [Background technology]

[0002] As a container for containing liquids such as liquid reagents and blood, a container with a convex bottom such as a round bottom or a cone bottom is known so that it can be directly put into a centrifuge or the like. As such a container, a free-standing container is known in which a skirt part for self-supporting is integrally formed at the lower end of the container body so as to surround the convex bottom so that it can be stored and housed in a free-standing state. Patent Document 1 proposes a free-standing specimen container with a threaded mouth part and a cylindrical skirt part integrally formed around the cone bottom. Patent Document 2 (FIG. 2) also proposes a free-standing reagent container with a cylindrical skirt part integrally formed around the cone bottom and a mouth part that can be plugged. In addition, various types of free-standing centrifuge tubes made of resin (PP) are commercially available. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 53-74985 [Patent Document 2] JP 2000-46624 A Summary of the Invention [Problem to be solved by the invention]

[0004] In many cases, such free-standing containers are made of resin molded products from the viewpoints of cost, ease of molding, etc. In this case, it is considered to manufacture a free-standing resin container by using cold parison injection blow molding, as in the case of PET bottles for beverages. However, no blow molding method suitable for manufacturing a free-standing resin container in which a skirt portion for supporting the container is integrally formed surrounding a convex bottom portion has been proposed.

[0005] In view of this, the object of the present invention is to propose a blow molding method suitable for producing a free-standing resin container in which a skirt portion for supporting the container is integrally formed surrounding a convex bottom portion, and to provide a free-standing resin container obtained using the molding method and a primary molded body which is a resin injection-molded product used to produce the resin container. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a cylindrical container body having a container mouth, a container body, and a convex container bottom; a cylindrical container skirt portion that surrounds the container bottom from a lower end of the container body portion and protrudes downward from the container bottom so that the container main body portion can stand on its own; A method for molding a self-supporting resin container comprising: A primary molded article is prepared, which is an injection-molded product made of resin and includes a cylindrical main body having a mouth, a body, and a bottom, and a cylindrical skirt portion that surrounds the bottom from a lower end of the body and protrudes downward from the bottom, a heating step of heating a portion of the primary molded body excluding the mouth portion and the foot portion to a predetermined temperature state; a blow molding process in which the heated primary molded body is set in a blow molding die with the mouth and the leg portions respectively held, and compressed air is blown into the body portion through the mouth portion to blow the body portion into the container body portion having a larger diameter than the body portion of the primary molded body; Through The method is characterized in that the mouth and skirt portions of the primary molded body remain as the container mouth and container skirt portions, and the body portion is blow molded into the container body portion having a larger diameter than the container skirt portion to obtain the resin container.

[0007] The present invention also provides a self-supporting resin container obtained by blow molding a primary molded article, which is a resin injection molded product, using the above-mentioned method for molding a self-supporting resin container, comprising: a cylindrical container body having a container mouth, a container body, and a convex container bottom; a cylindrical container skirt portion that surrounds the container bottom from a lower end of the container body portion and protrudes downward from the container bottom so that the container body portion can stand on its own; It is equipped with The container body has a body portion having a diameter larger than that of the container skirt portion, the container mouth portion and the container skirt portion are portions that are not blow molded and are the injection molded portions of the primary molded body remaining as they are, The container body is characterized in that it is a portion that has been subjected to blow molding.

[0008] Here, the container bottom may be a conical bottom that protrudes in a conical shape or a round bottom that protrudes in a hemispherical shape, and the container skirt may be a cylindrical skirt that coaxially surrounds the container bottom, or a truncated cone skirt that coaxially surrounds the container bottom and has a gradually increasing diameter downward.

[0009] The container mouth may be a threaded container mouth having a male thread formed on the outer circumferential surface for attaching a cap, or a container mouth shaped to be cappable.

[0010] Next, the present invention provides a primary molded article made of resin, which is an injection molded product suitable for use in the molding method for the above-mentioned self-supporting resin container, comprising: a cylindrical body having a mouth, a body and a convex bottom; a cylindrical skirt portion that surrounds the bottom portion from a lower end of the body portion and protrudes downward from the bottom portion so that the main body portion can stand on its own; It is equipped with the mouth portion and the skirt portion are not blow molded, and remain as they are as a container mouth portion and a container skirt portion of the self-supporting resin container, The body portion is characterized in that it is a portion that is blow molded to form a container body portion of the self-supporting resin container having a larger diameter than the body portion. Effect of the Invention

[0011] According to the method for molding a free-standing resin container of the present invention, while the mouth and skirt of a primary molded article, which is an injection-molded resin product, are held, blow molding is performed on the body between them, leaving the mouth and skirt as they are as the container mouth and container skirt, and blow molding the part between them into the large-diameter container body. This makes it possible to manufacture by blow molding a free-standing resin container with a complex cross-sectional shape in which a small-diameter free-standing container skirt is integrally formed in a state surrounding the container bottom that closes the lower end of the large-diameter container body. [Brief description of the drawings]

[0012] [Figure 1A] 1 is a front view showing an example of a free-standing resin container to which the present invention is applied, with a portion thereof shown in a cutaway state. [Figure 1B] 1B is a front view showing an example of a primary molded body, which is a resin injection-molded product used to mold the free-standing resin container shown in FIG. 1A. FIG. [Figure 1C] 1B to form the self-supporting resin container shown in FIG. 1A; FIG. [Figure 2A] FIG. 11 is a front view showing another example of a free-standing resin container to which the present invention is applied, with a part of the container shown in a cutaway state. [Figure 2B]2B is an explanatory diagram showing a vertical cross section of an example of a primary molded body that is an injection-molded resin product used to mold the free-standing resin container shown in FIG. 2A. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A self-supporting resin container and a molding method thereof according to an embodiment of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiment described below.

[0014] (Freestanding resin container) 1A is a front view of an example of a free-standing resin container to which the present invention is applied, with a portion of the container cut away. The free-standing resin container 1 comprises a bottomed, tubular container body 2 and a free-standing container skirt 6 formed integrally with the bottom of the container body 2. The container body 2 comprises a cylindrical container mouth 3 that opens upward, a cylindrical container body 4 that extends coaxially from the lower end of the container mouth 3, and a container bottom 5 that seals the lower end of the container body 4.

[0015] The container mouth 3 is a threaded container mouth with a male thread 3a for attaching a cap formed on its outer circumferential surface, and a support ring 3b is formed below the male thread 3a. The container body 4 below the container mouth 3 is a cylindrical body part that is one size larger than the container mouth 3. The container bottom 5 sealing the lower end of the container body 4 has a convex bottom 5a that protrudes downward in a cone shape at its center side. The container bottom 5 is integrally formed with a container skirt 6 that is cylindrical and has a smaller diameter than the container body 4 so as to coaxially surround the convex bottom 5a. The annular lower end surface 6a of the container skirt 6 is located on a perpendicular plane perpendicular to the container central axis 1a. Therefore, the resin container 1 can be stood on a flat surface.

[0016] The resin container 1 having this configuration is, for example, a molded product made of polyethylene or polypropylene resin, and is manufactured by subjecting a primary molded product, which is an injection molded product, to blow molding.

[0017] (Primary molded body) 1B is a front view showing an example of a primary molded body, which is a resin injection-molded product used for blow molding a resin container 1. The primary molded body 10 includes a bottomed tubular main body 12 and a self-supporting skirt portion 16 formed integrally with the bottom of the main body 12. The main body 12 includes a cylindrical mouth portion 13 that opens upward, a cylindrical body portion 14 that extends coaxially from the lower end of the mouth portion 13, and a bottom portion 15 that seals the lower end of the body portion 14.

[0018] The mouth 13 is a threaded mouth having a male thread 13a for attaching a cap formed on its outer circumferential surface, and a support ring 13b is formed below the male thread 13a. The body 14 below the mouth 13 is cylindrical and has the same diameter as the mouth 13. The bottom 15 sealing the lower end of the body 14 is a convex bottom with its central portion protruding downward in a cone shape. A skirt 16 is integrally formed and cylindrical with the same diameter as the body 4 or a slightly smaller diameter so as to coaxially surround the bottom 15. The annular lower end surface 16a of the skirt 16 is located on an orthogonal plane perpendicular to the central axis 10a of the molded body.

[0019] (Blow molding procedure for freestanding resin containers, blow mold) 1C is an explanatory diagram showing an example of a molding procedure for a resin container 1 and an example of a blow molding die. A primary molded body 10, which is an injection molded product, is supplied to a molding line 22 at a supply station 21 (supply step ST1). The primary molded body 10 is transported along the molding line 22 via a heating station 23 and heated (heating step ST2). The heated primary molded body 10, which is in a temperature state suitable for blow molding, is transported along the molding line 22 to a blow station 24, where it is set in a blow molding die 40 and subjected to blow molding (blow molding step ST3). The molded resin container 1 is removed from the blow molding die and transported along the molding line 22 to a recovery station 25 and recovered (recovery step ST4).

[0020] For example, the mouth portion 13 of the primary molded body 10 is gripped by the conveying tool 30, and in this state, the primary molded body 10 is conveyed by the conveying tool 30 along the molding line 22. In the heating step ST2, the mouth portion 13 of the primary molded body 10 is covered and hidden by the conveying tool 30, and the skirt portion 16 is also heated while being covered and hidden by a shielding member (not shown), and the body portion 14, which is a portion formed in the container body 4, excluding the mouth portion 13 and the skirt portion 16, is heated.

[0021] The heated primary molded body 10 is set in the blow mold 40 by the carrier 30. The blow mold 40 is composed of, for example, left and right open-close molds 41, 42 and a bottom mold 43. The upper end inner peripheral surfaces 41a, 42a of the left and right open-close molds 41, 42 are mouth gripping parts capable of gripping the lower side of the support ring 13b of the primary molded body 10 from the left and right. The lower end inner peripheral surfaces 41b, 42b of the left and right open-close molds 41, 42 are skirt gripping parts capable of gripping the skirt portion 16 of the primary molded body 10 from the left and right. The upper end inner peripheral surfaces 41a, 42a and the lower end inner peripheral surfaces 41b, 42b of the open-close molds 41, 42 are container body shaping surfaces 41c, 42c. On the other hand, the bottom mold 43 is formed with a mold surface corresponding to the lower surface of the bottom 15 of the primary molded body 10, the inner peripheral surface of the skirt portion 16, and the lower end surface.

[0022] The primary molded body 10 is set in the blow molding die 40 with the support ring lower portion 13c of the mouth 13 and the skirt portion 16 held by the left and right open-close dies 41, 42, respectively. In this state, compressed air is blown into the inside of the body 14 through the mouth 13 from above, blowing the body 14 and molding it into a container body 4 having a larger diameter than the body 14. As a result, in the obtained resin container 1, the mouth 13, the skirt portion 16 and the bottom portion 15 surrounded by the skirt portion 16 of the primary molded body 10 remain as they are as the container mouth 3, the container skirt portion 6 and the convex bottom portion 5a surrounded by the container skirt portion 6, and the body portion 14 of the primary molded body 10 is blow molded into the container body 4 shown in FIG. 1A having a larger diameter than the container skirt portion 6.

[0023] (Another example of a free-standing plastic container) Fig. 2A is a front view showing another example of a free-standing resin container to which the present invention is applied, and is shown in a partially cut state. Fig. 2B is an explanatory diagram showing an example of a primary molded body, which is a resin injection-molded product used to mold the free-standing resin container shown in Fig. 2A, and is shown in longitudinal section excluding the mouth portion.

[0024] The basic configuration of the free-standing resin container 50 and primary molded body 60 shown in these figures is the same as that of the resin container 1 and primary molded body 10 shown in Figures 1A and 1B, with the difference being that the skirt portion is not cylindrical but has a truncated cone shape with a diameter that gradually increases toward the bottom.

[0025] Specifically, the self-supporting resin container 50 (hereinafter, simply referred to as the "resin container 50") includes a bottomed cylindrical container body 52 and a self-supporting container skirt 56 formed integrally with the bottom of the container body 52. ​​The container body 52 includes a cylindrical container mouth 53 that opens upward, a cylindrical container body 54 that extends coaxially from the lower end of the container mouth 53, and a container bottom 55 that seals the lower end of the container body 54. The container mouth 53 is a threaded container mouth with a male thread 53a for attaching a cap formed on its outer circumferential surface, and a support ring 53b is formed below the male thread 53a. The container body 54 below the container mouth 53 is a cylindrical body portion that is one size larger than the container mouth 53. The container bottom 55 that seals the lower end of the container body 54 has a convex bottom 55a that protrudes downward in a conical shape at its center side. A cylindrical container skirt portion 56 having a smaller diameter than the container body portion 54 is integrally formed with the container bottom portion 55 so as to coaxially surround the convex bottom portion 55a. The annular lower end surface 56a of the container skirt portion 56 is a flat surface perpendicular to the container central axis 50a, allowing the resin container 50 to stand on its own. The resin container 1 is, for example, a molded product of polypropylene resin, and is manufactured by blow molding a primary molded body 60, which is an injection molded product.

[0026] The primary molded body 60 includes a bottomed cylindrical main body 62 and a skirt portion 66 for self-supporting that is integrally formed on the bottom of the main body 62. The main body 62 includes a cylindrical mouth 63 that opens upward, a cylindrical body 64 that extends coaxially from the lower end of the mouth 63, and a bottom 65 that seals the lower end of the body 64. The mouth 63 is a threaded mouth with a male thread 63a for attaching a cap formed on its outer circumferential surface, and a support ring 63b is formed below the male thread 63a. The body 64 below the mouth 63 has a cylindrical shape with the same diameter as the mouth 63. The bottom 65 that seals the lower end of the body 64 is a convex bottom with its center portion protruding downward in a cone shape. A skirt portion 66 in a truncated cone shape is integrally formed so as to coaxially surround the bottom 65. The upper end of the skirt portion 66 has the same diameter as the body portion 64, and the annular lower end surface 66a, which has the largest diameter, forms a flat surface perpendicular to the central axis 60a of the molded body.

[0027] The resin container 50 having this configuration is also obtained by blow molding the primary molded body 60, similarly to the resin container 1. That is, the body 64, which is the portion formed in the container body 54 excluding the mouth 63 and skirt 66 of the primary molded body 60, is heated, and blow molding is performed while each of the mouth 63 and skirt 66 is held. In the obtained resin container 50, the mouth 63, skirt 66, and bottom 65 surrounded by the skirt 66 of the primary molded body 60 remain as they are as the container mouth 53, container skirt 56, and convex bottom 55a surrounded by the container skirt 56, and the body 64 of the primary molded body 60 is blow molded into the container body 54 shown in FIG. 2A, which has a larger diameter than the container skirt 56.

[0028] (Other embodiments) The above example relates to a plastic container having a threaded container mouth for attaching a cap, but the present invention is equally applicable to free-standing plastic containers having a container mouth of a pluggable shape that allows the container mouth to be closed with a cap or other plug or seal other than a screw-on cap. In addition, the shape of the skirt portion for allowing the resin container to stand on its own is not limited to a cylindrical shape or a truncated cone shape, but may be any shape that allows injection molding and allows the container to stand on its own. In other words, since this part is not blow molded, it may be in various shapes. Furthermore, various thermoplastic resins other than polyethylene and polypropylene can be used as the resin for molding the container. [Explanation of symbols]

[0029] 1, 50 Resin container 1a, 50a Container center axis 2, 52 Container body 3, 53 Container opening 3a, 53a male thread 3b, 53b support ring 4, 54 Container body 5, 55 Bottom of container 5a, 55a convex bottom 6, 56 Container skirt 6a, 56a Bottom end surface 10, 60 Primary molded object 10a, 60a Center axis of molded object 12, 62 Main body 13, 63 Mouth 13a, 63a male thread 13b, 63b support ring 13c Lower part of support ring 14, 64 Torso 15, 65 bottom 16, 66 Skirt section 16a, 66a Bottom end surface 21 Supply Station 22 Molding Line 23 Heating Station 24 Blow Station 25 Collection Station 30 Transport Equipment 40 Blow mold 41, 42 Open / close type 43 Bottom type 41a, 42a Inner circumferential surface of upper end portion (mouth grip portion) 41b, 42b Inner peripheral surface of lower end portion (scratched grip portion) 41c, 42c Container body shaping surface ST1 Supply Engineering ST2 Heating Engineering ST3 ブローforming process ST4 Recycling Engineering

Claims

1. a cylindrical container body having a container mouth, a container body, and a convex container bottom; a cylindrical container skirt portion that surrounds the container bottom from a lower end of the container body portion and protrudes downward from the container bottom so that the container main body portion can stand on its own; A method for molding a self-supporting resin container comprising: A primary molded article is prepared, which is an injection-molded product made of resin and includes a cylindrical main body having a mouth, a body, and a bottom, and a cylindrical skirt portion that surrounds the bottom from a lower end of the body and protrudes downward from the bottom, a heating step of heating a portion of the primary molded body excluding the mouth portion and the skirt portion to a predetermined temperature state suitable for blow molding; a blow molding process in which the heated primary molded body is set in a blow molding die with the mouth portion and the skirt portion being gripped, and compressed air is blown into the body portion through the mouth portion to blow the body portion into the container body portion having a larger diameter than the body portion; Through A method for molding a self-supporting resin container, characterized in that the mouth and skirt portions of the primary molded body remain as the container mouth and container skirt portions, and the body portion is blow molded into a container body having a larger diameter than the container skirt portion to obtain the resin container.

2. A self-supporting resin container obtained by blow molding a primary molded article that is a resin injection molded product, a cylindrical container body having a container mouth, a container body, and a convex container bottom; a cylindrical container skirt portion that surrounds the container bottom from a lower end of the container body portion and protrudes downward from the container bottom so that the container body portion can stand on its own; It is equipped with The container body has a body portion having a diameter larger than that of the container skirt portion, the container mouth portion and the container skirt portion are portions that are not blow molded and are the injection molded portions of the primary molded body remaining as they are, A self-supporting resin container, wherein the container body is a portion that has been subjected to blow molding.

3. The self-supporting resin container according to claim 2, The bottom of the container is a conical bottom that protrudes in a conical shape or a round bottom that protrudes in a hemispherical shape, The container skirt portion is a cylindrical skirt coaxially surrounding the vessel bottom; or A free-standing resin container having a truncated cone-shaped skirt coaxially surrounding the container bottom and gradually increasing in diameter downward.

4. The self-supporting resin container according to claim 3, The container mouth portion is A threaded container mouth having a male thread formed on the outer periphery for attaching a cap, or A container mouth that can be closed It is a free-standing resin container.

5. A primary molded article which is a resin injection-molded product used for manufacturing the self-supporting resin container according to claim 2, a cylindrical body having a mouth, a body and a convex bottom; a cylindrical skirt portion that surrounds the bottom portion from a lower end of the body portion and protrudes downward from the bottom portion so that the main body portion can stand on its own; Equipped with the mouth portion and the skirt portion are not blow molded, and remain as they are as a container mouth portion and a container skirt portion of the self-supporting resin container, The body portion is a primary molded body of a free-standing resin container, characterized in that the body portion is a portion that is blow molded to form a container body portion of the free-standing resin container having a larger diameter than the body portion.

6. The primary molded article of the self-supporting resin container according to claim 5, The bottom is a conical bottom that protrudes in a conical shape or a round bottom that protrudes in a hemispherical shape, The skirt portion is a cylindrical skirt coaxially surrounding said base; or A primary molded article for a self-supporting resin container is a truncated cone-shaped skirt that coaxially surrounds the bottom and gradually increases in diameter downward.

7. The primary molded article of the self-supporting resin container according to claim 6, The mouth portion is A threaded mouth portion having male threads formed on the outer periphery for attaching a cap, or Mouth shaped to be pluggable This is the primary molded body of a free-standing resin container.

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