Plastic container

Abstract

Provided is a plastic container which is lightweight, has excellent cleanliness and leakage resistance of contents, and has excellent sealing properties during storage and transportation, in particular, a plastic container which is suitable for being filled with a high-specific-gravity and high-viscosity solution such as a CMP slurry, and which satisfies the UN standard, and which is suitable for storage and transportation. A first threaded part (8) is formed on the inner surface of a cylindrical body (7), a second threaded part (16) capable of being screwed to the first threaded part (8) is formed on the outer surface of an upper member (13) of a plug (12), and a gasket (21) is interposed between the outer surface of the plug (12) and the inner surface of a mouth part (5) so as to be in contact with the outer surface of the plug (12) and the inner surface of the mouth part (5). A raised portion (25) is formed on the inner surface of the mouth portion (5) so as to be capable of being in contact with the pad (21).

Description

Technical Field

[0001] The present invention relates to a plastic container suitable for filling, storing, and transporting solutions such as CMP slurry and meeting UN standards. Background Art

[0002] Conventionally, in storage and transportation, containers such as paper containers, glass containers, metal containers, and plastic containers have been widely used according to the container performance requirements such as light weight, mechanical strength, and cleanliness.

[0003] In addition, in recent years, with the development of the industry, it has been widely carried out industrially to fill containers with high-viscosity solutions such as high-viscosity foods, pharmaceutical solutions, CMP slurries, photoresists, and developers, store them, and transport them. These high-viscosity solutions have a high specific gravity and are heavy, and the discharge is usually carried out through a dispenser. Therefore, the container is required to have high mechanical strength.

[0004] Therefore, various solutions have been proposed as containers for the above high-viscosity solutions. For example, in Patent Document 1, a description is made of the mouthplug portion of a resin cylinder. As shown in the cross-sectional view of Figure 11 "The cylinder mouth portion 41 has an internal thread 42 and is threadedly engaged with a plug 44 having an external thread 43. A gasket 45 is disposed below the thread, and a sealing surface is formed by the protruding end surface 46 of the cylinder mouth portion 41 and the horizontal end surface 47 of the plug 44. Two annular protrusions 48a, 48b are formed on the outer periphery of the cylinder mouth portion 41. As shown in the cross-sectional view of Figure 12 when a dust-proof cap 49 is installed, the protrusion 48b is engaged with the protrusion 50 of the dust-proof cap 49 to function as an anti-disengagement member. As shown in the cross-sectional view of Figure 13 when a safety sealing cap 51 is installed, the protrusion 48a is engaged with the protrusion 52 of the sealing cap 51 to function as an anti-disengagement member. As shown in the cross-sectional view of Figure 11 the upper end surface 53 of the cylinder mouth portion 41 is located at a position higher than the upper end surface 56 of the L-shaped ring 55 of the resin cylinder 54 and lower than the cylinder top surface 57."

[0005] The mouthplug portion of the above resin cylinder has a gasket 45 between the resin cylinder 54 and the plug 44. On the other hand, high-viscosity solutions such as CMP slurry contain fillers with a high specific gravity such as abrasives, metal powders, and inorganic fillers. Therefore, during storage and transportation, the fillers precipitate and cannot be used directly. Therefore, before use, the above resin cylinder is supplied to a rotating device or a vibrating device, and rotated or vibrated to uniformly stir the above high-viscosity solution before use. However, only having a gasket 45 has the disadvantage that the high-viscosity solution leaks when rotated or vibrated.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Laid-Open No. 11-342962 Summary of the Invention

[0009] (1) Technical Problem to be Solved

[0010] In view of the above problems, an object of the present invention is to provide a plastic container that is lightweight, has excellent cleanliness and leakage resistance of the contents, and has excellent sealing performance during storage and transportation. In particular, it is a plastic container that is suitable for filling solutions with high specific gravity and high viscosity such as CMP slurry and for storage and transportation, and meets the UN standards.

[0011] (2) Technical Solution

[0012] The first invention of the present application for achieving the above object is a plastic container, which includes a container body formed with a mouth portion and a plug for closing the mouth portion. The plastic container is characterized in that a first thread portion is formed on the inner surface of the mouth portion, a second thread portion that can be threadedly engaged with the first thread portion is formed on the outer surface of the plug, a gasket is interposed between the outer surface of the plug and the inner surface of the mouth portion in a manner of abutting against the outer surface of the plug and the inner surface of the mouth portion, and in the plastic container, a raised portion is formed on the inner surface of the mouth portion in a manner of being able to contact the gasket.

[0013] The second invention of the present application is a plastic container, which is characterized in that in the first invention of the present application, a raised portion is formed below the second thread portion on the outer surface of the plug.

[0014] The third invention of the present application is a plastic container, which is characterized in that in the first invention of the present application, a raised portion is formed below the first thread portion on the inner surface of the mouth portion.

[0015] The fourth invention of the present application is a plastic container, which is characterized in that in the second invention of the present application, a raised portion is formed below the first thread portion on the inner surface of the mouth portion.

[0016] The fifth invention of the present application is a plastic container, which is characterized in that in any one of the first to fourth inventions of the present application, grooves are respectively formed on the outer surface of the plug and the inner surface of the mouth portion at the portion where the gasket abuts.

[0017] The sixth invention of the present application is a plastic container, which is characterized in that in the fifth invention of the present application, a protrusion is formed on the inner surface of the mouth portion at the portion where the gasket abuts.

[0018] The seventh invention of the present application is a plastic container, which is characterized in that in the fifth invention of the present application, a protrusion is formed on the outer surface of the plug at the portion where the gasket abuts.

[0019] The eighth invention of the present application is a plastic container, which is characterized in that in the sixth invention of the present application, a protrusion is formed on the outer surface of the plug at the portion where the gasket abuts.

[0020] The ninth invention of the present application is a plastic container, characterized in that, in the eighth invention of the present application, the gasket is an O-ring.

[0021] The tenth invention of the present application is a plastic container, characterized in that, in the ninth invention of the present application, a lid covers the mouth portion.

[0022] The eleventh invention of the present application is a plastic container, characterized in that, in the tenth invention of the present application, the roundness of the mouth portion is 1.0 mm or less.

[0023] (III) Advantageous Effects

[0024] The plastic container of the present invention is configured as described above, is lightweight, has high mechanical strength, high cleanliness and airtightness, excellent leakage resistance of the content, and excellent sealing performance during storage and transportation. It is particularly suitable for storing and transporting high-specific gravity and high-viscosity solutions such as CMP slurries. Description of the Drawings

[0025] Figure 1 (A) of is a side view showing an example of the plastic container of the present invention, Figure 1 and (B) of is a top view thereof.

[0026] Figure 2 is a cross-sectional view showing an example of the mouth portion in the plastic container of the present invention.

[0027] Figure 3 (A) of is a cross-sectional view showing an example of the plug in the plastic container of the present invention, Figure 3 and (B) of is a bottom view thereof.

[0028] Figure 4 is a cross-sectional view showing an example of the state after closing the mouth portion of the plastic container of the present invention.

[0029] Figure 5 is a cross-sectional view showing a different example of the state after closing the mouth portion of the plastic container of the present invention.

[0030] Figure 6 (A) of, Figure 6 (B) of is a cross-sectional view showing yet another different example of the state after closing the mouth portion of the plastic container of the present invention.

[0031] Figure 7 (A) of, Figure 7 (B) of is a view for explaining the gap between the raised portion and the opposing member.

[0032] Figure 8 is a cross-sectional view showing yet another different example of the state after closing the mouth portion of the plastic container of the present invention.

[0033] Figure 9 It is a cross-sectional view showing another different example of the state after closing the mouth of the plastic container of the present invention.

[0034] Figure 10 It is a cross-sectional view showing another different example of the state after closing the mouth of the plastic container of the present invention.

[0035] Figure 11 It is a partial cross-sectional view showing the details of the mouth plug portion of the resin cylinder described in Patent Document 1.

[0036] Figure 12 It is a cross-sectional view showing the state in which a dust-proof cover is attached to the mouth plug portion of the resin cylinder described in Patent Document 1.

[0037] Figure 13 It is a cross-sectional view showing the state in which a safety seal cover is attached to the mouth plug portion of the resin cylinder described in Patent Document 1. Detailed Description of the Invention

[0038] The plastic container of the first invention of the present application includes a container body having a mouth formed thereon and a plug for closing the mouth. A first thread portion is formed on the inner surface of the mouth, and a second thread portion capable of being threadedly engaged with the first thread portion is formed on the outer surface of the plug. A gasket is interposed between the outer surface of the plug and the inner surface of the mouth in a manner of abutting against the outer surface of the plug and the inner surface of the mouth. The plastic container is characterized in that a raised portion is formed on the inner surface of the mouth in a manner capable of contacting the gasket.

[0039] The shape of the plastic container is not particularly limited, and a substantially cylindrical shape, a barrel shape, or a prismatic shape is preferred. The plastic container is preferably made of plastic.

[0040] The plastic is any known resin such as natural resin, thermoplastic resin, and thermosetting resin that has been used as a material for liquid containers in the past. A thermoplastic resin having excellent thermoformability, high mechanical strength, and excellent cleanliness is preferred, and an olefin resin is particularly preferred.

[0041] The above-mentioned olefin resin is a polymer polymerized mainly from olefin monomers such as ethylene monomer and propylene monomer. Examples thereof include ethylene homopolymers such as high-density polyethylene resin, medium-density polyethylene resin, and low-density polyethylene resin, copolymers of ethylene as the main component with α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, and 1-heptene, homopolypropylene resin, atactic polypropylene resin and other propylene homopolymers, copolymers of propylene as the main component with α-olefins such as ethylene, 1-butene, 1-hexene, 1-pentene, and 1-heptene, etc. High-density polyethylene resin, medium-density polyethylene resin, homopolypropylene resin, and atactic polypropylene resin that can obtain containers with high mechanical strength and excellent self-standing properties are preferred, and high-density polyethylene resin and polypropylene resin are more preferred. In addition, these olefin resins can be used alone or in combination of two or more olefin resins.

[0042] Next, the plastic container of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the same or similar components are denoted by the same reference numerals.

[0043] Figure 1 (A) is a side view showing an example of the plastic container of the present invention, Figure 1 (B) is a top view thereof. In Figure 1 (A), 1 is a barrel-shaped container body composed of an upper wall portion 2, a side wall portion 3, and a bottom wall portion 4. An opening 5 and an air port 6 are formed in the upper wall portion 2. The air port 6 is an opening for the purpose of easily discharging the stored liquid and is connected to a pressurizing device to make the inside of the container in a pressurized state. When discharging the stored liquid, air is injected so that the inside of the container is not decompressed and the discharge speed of the stored liquid does not decrease. Of course, the air port 6 is closed during the process of filling the container body 1 with the stored liquid for storage and transportation. In addition, a plurality of air ports 6 may be provided. In addition, the structure of the air port 6 is not particularly limited, and it may be only an opening, a cylindrical shape, or the same shape as the opening in the present invention.

[0044] The manufacturing method of the above-mentioned container body is not particularly limited. In the case of being composed of an olefin resin, it is preferably formed by blow molding an olefin resin. As the blow molding method, any conventionally known blow molding method can be adopted. For example, extrusion blow molding, injection blow molding, stretch blow molding, multi-layer blow molding, etc. can be cited.

[0045] Figure 2FIG. 0 is a cross-sectional view showing an example of the mouth portion 5 of the container body 1 of the above-mentioned plastic container. The mouth portion 5 has a cylindrical body 7 located above the upper wall portion 2 of the container body 1, and the storage liquid can be injected and discharged. A first thread portion 8 is formed near the upper portion of the inner surface of the cylindrical body 7. A substantially flat plate-shaped protrusion 10 is formed below the first thread portion 8 and protrudes inward in a substantially horizontal direction via an inclined portion 9. Moreover, the front end of the protrusion 10 faces vertically downward, and its lowermost end is connected to the upper wall portion 2 to form the mouth portion 5. A groove 11 having a substantially arc-shaped cross-section is formed on the upper surface of the protrusion 10, and a part of an O-ring, that is, a gasket, described later can be fitted into the groove 11 that is slightly recessed inward from the upper surface of the protrusion 10.

[0046] Figure 3 FIG. (A) of Figure 3 is a cross-sectional view showing an example of the plug 12 in the plastic container of the present invention. Figure 3 FIG. (B) of Figure 3 is a bottom view thereof. The plug 12 is composed of a disc-shaped upper member 13 and a disc-shaped lower member 14. The diameter of the upper member 13 is larger than the diameter of the lower member 14, and the upper member 13 and the lower member 14 are laminated concentrically and integrally formed. In addition, reinforcing ribs are erected on the side surface of the upper member 13 to form a side wall 15, and a second thread portion 16 is formed on the side wall 15. The second thread portion 16 can be threadedly engaged with the first thread portion 8 formed on the inner surface of the cylindrical body 7. A groove 18 having a substantially arc-shaped cross-section is formed on the lower surface 17 of the outer peripheral edge portion of the upper member 13, and a part of an O-ring, that is, a gasket, described later can be fitted into the groove 18 that is slightly recessed inward from the lower surface 17 of the outer peripheral edge portion.

[0047] Figure 4 FIG. is a cross-sectional view showing an example of the state after closing the mouth portion of the plastic container of the present invention. The second thread portion 16 formed on the side wall 15 of the upper member 13 of the plug 12 is threadedly engaged with the first thread portion 8 formed on the inner surface of the cylindrical body 7. By threadedly engaging the second thread portion 16 with the first thread portion 8, a gasket 21 as an O-ring abuts against the side surface 20 of the outer peripheral wall 19 of the lower member 14 of the plug 12 and the inner surface 9a of the inclined portion 9 of the cylindrical body 7, and a part of the gasket 21 as an O-ring is fitted into the groove 11 and the groove 18. In this way, the gasket 21 contacts the outer surface of the plug 12 and the inner surface of the mouth portion 5 at four positions and is clamped and pressed, so that the mouth portion 5 can ensure excellent airtightness. Since the gasket 21 is made of a plastic material, the gasket 21 may be compressed and deformed when it is clamped and pressed. In order to improve the sealing performance, it is preferable that the inner diameter of the gasket 21 is the same as or slightly smaller than the outer diameter of the lower member 14, and as long as a part of the gasket 21 can be fitted into the groove 11 and the groove 18, the diameter of the gasket 21 is preferably slightly larger than the height of the side surface 20 of the outer peripheral wall 19 of the lower member 14.

[0048] The lid 22 is made of plastic and covers the mouth portion 5 to protect and strengthen the sealed portion. As the lid 22, for example, it can be configured to cover the mouth portion 5 by pressing and be in close contact with the cylindrical body 7 and the inclined portion 9. When a threaded portion th is formed on the outer surface of the mouth portion 5, it can also be configured to have a threaded portion on the inner surface of the lid 22 that can be threadedly engaged with the threaded portion th.

[0049] If there is strain in the cylindrical body 7 and it is not a perfect circle, the sealing performance will decrease, sometimes resulting in liquid leakage or the plug falling off. Therefore, it is preferred that the planar shape of the cylindrical body 7 is a perfect circle. That is, it is preferred that the roundness of the cylindrical body 7 is high, more preferably 1.0 mm or less, and further preferably 0.8 mm or less.

[0050] In the present invention, the roundness refers to the difference between the length of the major axis and the length of the minor axis on the upper surface of the cylindrical body 7, with the unit being mm. Additionally, when manufacturing a plastic container by blow molding, since it becomes an ellipse with the PL (parting line) direction as the major axis, it is also possible to measure the lengths in the PL direction and the direction perpendicular to it, and set the difference as the roundness. The smaller the difference, the higher the roundness.

[0051] The second threaded portion 16 formed on the side wall 15 of the upper part 13 is threadedly engaged with the first threaded portion 8 formed on the inner surface of the cylindrical body 7. Therefore, if the upper part 13 has strain and is not a perfect circle, the airtightness cannot be ensured. As a result, the sealing performance decreases, sometimes resulting in liquid leakage or the plug 12 falling off. Therefore, it is preferred that the planar shape of the upper part 13 is also a perfect circle. That is, it is preferred that the roundness of the upper part 13 is high, more preferably 1.0 mm or less, and further preferably 0.8 mm or less.

[0052] In this specification, an O-ring is a solid or hollow ring-shaped body, and its cross-sectional shape is not particularly limited. For example, a circle, an ellipse, a quadrilateral, a hexagon, etc. can be cited. However, in order not to age (Japanese: へたり) and deform over time, a circle is preferred. Therefore, the O-ring is preferably a solid or hollow ring-shaped body with a circular cross-sectional shape.

[0053] By the threaded engagement of the second threaded portion 16 and the first threaded portion 8, a part of the gasket 21 as the O-ring is inserted into the groove 11 and the groove 18. The gasket 21 is held and pressed in contact with the outer surface of the plug 12 and the inner surface of the mouth portion 5 at four positions, thereby ensuring excellent airtightness of the mouth portion 5. Therefore, if the gasket 21 as the O-ring is too hard, its toughness decreases, and over time, the sealing performance is likely to decrease. If it is too soft, it is prone to aging and the wear resistance decreases, resulting in a decrease in the sealing performance. Therefore, the hardness (Durometer D) of the gasket 21 is preferably 40 - 48. Additionally, in the present invention, the hardness (Durometer D) is a value measured in accordance with JIS K 7215 - 1986.

[0054] Since a gasket 21 in the form of an O-ring is clamped between the upper surface of the protruding portion 10 protruding from the inner surface of the cylindrical body 7 and the lower surface 17 of the outer peripheral edge portion of the upper member 13 of the plug 12 to improve the sealing performance of the container body 1, it is preferable that the upper surface of the protruding portion 10 and the lower surface 17 of the outer peripheral edge portion of the upper member 13 are both substantially horizontal and parallel.

[0055] In order to clamp the gasket 21 in the form of an O-ring between the upper surface of the protruding portion 10 protruding from the inner surface of the cylindrical body 7 and the lower surface 17 of the outer peripheral edge portion of the upper member 13 of the plug 12 to improve the sealing performance of the container body 1, it is preferable that the protruding portion 10, the upper member 13, and the gasket 21 in the form of an O-ring are more closely attached.

[0056] If the surface smoothness of the upper surface of the protruding portion 10 and the lower surface 17 of the outer peripheral edge portion of the upper member 13 with which the gasket 21 in the form of an O-ring comes into contact becomes high, the surface pressure applied to the surface of the gasket 21 in the form of an O-ring is uneven, and the sealing performance is reduced. Therefore, it is preferable that the above surface smoothness is small.

[0057] Therefore, the surface smoothness of the upper surface of the protruding portion 10 and the lower surface 17 of the outer peripheral edge portion of the upper member 13 is preferably 0.30 mm or less, and more preferably 0.25 mm or less. For the same reason, the surface smoothness of the surface of the gasket 21 is also preferably 0.30 mm or less, and more preferably 0.25 mm or less.

[0058] Moreover, since the gasket 21 in the form of an O-ring is located on the upper surface of the protruding portion 10 on the inner surface of the cylindrical body 7, in order to improve the sealing performance, it is preferable that the surface smoothness of the upper surface of the protruding portion 10 is smaller, preferably 0.20 mm or less, and the surface smoothness of the upper surface of the protruding portion 10 is preferably 0.05 mm or more smaller than the surface smoothness of the lower surface 17 of the outer peripheral edge portion of the upper member 13 and the surface of the gasket 21.

[0059] In addition, the "surface smoothness" in the present invention is a value measured by a three-dimensional measuring instrument (manufactured by Mitutoyo Corporation, trade name "Quick Vision PRO").

[0060] As described above, if grooves (11, 18) having a cross-sectional shape such as an arc shape into which a part of the gasket 21 in the form of an O-ring can be inserted are formed on the upper surface of the protruding portion 10 formed on the inner surface of the cylindrical body 7 and / or the lower surface 17 of the outer peripheral edge portion of the upper member 13 of the plug 12, then when the first thread portion 8 formed on the inner surface of the cylindrical body 7 and the second thread portion 16 formed on the side wall 15 of the plug 12 are threadedly engaged, the plug 12 and the gasket 21 in the form of an O-ring are more strongly attached, and the sealing performance is improved. Therefore, it is preferable.

[0061] Furthermore, for the same reason, a groove having an arcuate cross-sectional shape or the like into which a part of the gasket 21 serving as an O-ring can be fitted may also be formed on the side surface 20 of the outer peripheral wall 19 of the lower member 14 of the plug 12.

[0062] The materials constituting the plug 12 and the gasket 21 are preferably olefin resins, more preferably high-density polyethylene resin or polypropylene resin. When the plug 12 and the gasket 21 serving as an O-ring are made of olefin resins, they are preferably formed by an injection molding method.

[0063] Figure 5 It is a cross-sectional view showing different examples of the state after closing the mouth of the plastic container of the present invention. The second thread portion 16 formed on the side wall 15 of the upper member 13 of the plug 12 is threadedly engaged with the first thread portion 8 formed on the inner surface of the cylindrical body 7a.

[0064] The gasket 21 serving as an O-ring is fitted so as to surround the side surface 20 of the outer peripheral wall 19 of the lower member 14 of the plug 12. On the upper surface of the substantially flat protruding portion 23 protruding substantially horizontally inward from the inner surface of the cylindrical body 7a, an upward protruding portion 24 is formed concentrically with the cylindrical body 7a, and the cylindrical body 7a is reduced in diameter toward the lower side, and a raised portion 25 that bulges inward is formed.

[0065] In addition, the upward protruding portion 24 may be formed upward concentrically with the cylindrical body 7a on the upper surface of the protruding portion 23, and its position is not particularly limited. It is preferably formed on the upper surface of the protruding portion 23 between directly below the center of the gasket 21 serving as an O-ring and the side surface 20 of the outer peripheral wall 19 of the lower member 14.

[0066] The cross-sectional shape of the upward protruding portion 24 is not particularly limited. For example, shapes such as a triangle, a semicircle, and an ellipse are preferred. In order to improve the sealing performance, the gasket 21 serving as an O-ring and / or the upward protruding portion 24 may also be compressed and deformed when being clamped and pressed by the front end portion of the gasket 21 serving as an O-ring and the upward protruding portion 24, the raised portion 25, the lower surface 17 of the outer peripheral edge portion of the upper member 13, and the side surface 20 of the outer peripheral wall 19 of the lower member 14.

[0067] By threadedly engaging the second thread portion 16 formed on the side wall 15 of the plug 12 with the first thread portion 8 formed on the inner surface of the cylindrical body 7a, the gasket 21 serving as an O-ring is clamped and pressed by the lower surface 17 of the outer peripheral edge portion of the upper member 13 of the plug 12, the side surface 20 of the outer peripheral wall 19 of the lower member 14, the front end portion of the upward protruding portion 24, and the raised portion 25, and the mouth portion 5 is sealed.

[0068] The gasket 21 serving as an O-ring is clamped by the raised portion 25. Therefore, the surface smoothness of the surface of the raised portion 25 is preferably 0.30 mm or less, more preferably 0.25 mm or less, and further preferably 0.20 mm or less. Moreover, the surface smoothness of the surface of the raised portion 25 is preferably 0.05 mm or more smaller than the surface smoothness of the surface of the gasket 19 serving as an O-ring.

[0069] Moreover, a protrusion can be formed at any one or more of the lower surface 17 of the outer peripheral edge portion of the upper member 13, the side surface 20 of the outer peripheral wall 19 of the lower member 14, or the raised portion 25. If such a protrusion is formed, the gasket 21 serving as an O-ring is clamped and pressed by more fulcrums, and thus is held more firmly, and the container body 1 is hermetically sealed more reliably. The cross-sectional shape of the protrusion can be the same as that of the upward protrusion 24.

[0070] Moreover, as shown in (A) of Figure 6 , a raised portion 26 can be provided on the side surface 20a of the outer peripheral wall 19a of the lower member 14, or as shown in (B) of Figure 6 , a raised portion 28 can be provided on the side surface 27 of the protrusion 23. By providing such raised portions 26 and 28, the following effects can be expected. That is, the gasket 21 is set on the plug 12 and then installed on the mouth portion 5. Therefore, if screw engagement is performed in a state where the gasket 21 is not installed in an appropriate position, the surface of the mouth portion 5, the surface of the plug 12, or the first thread portion 8 and the second thread portion 16 may be damaged. Therefore, by providing the raised portions 26 and 28 on the side surface 20a of the outer peripheral wall 19a of the lower member 14 and the side surface 27 of the protrusion 23, respectively, the positioning of the gasket 21 becomes easy, and the gasket 21 can be installed in an appropriate position. As a result, the surface of the mouth portion 5 and the surface of the plug 12 are not damaged, and the first thread portion 8 and the second thread portion 16 are not deformed. Therefore, the stored liquid does not leak, and the plug 12 does not fall off. It is sufficient to provide either the raised portion 26 or the raised portion 28 in the plastic container of the present invention. Of course, both the raised portion 26 and the raised portion 28 can be provided in the same plastic container.

[0071] Figure 7 The gap d1 between the front end portion of the raised portion 26 shown in (A) of Figure 7 and the protrusion 23 and the gap d2 between the front end portion of the raised portion 28 shown in (B) of

[0072] Figure 8It is a cross-sectional view showing another different example of the state after closing the mouth of the plastic container of the present invention. On the upper surface of the substantially flat protruding portion 29 that protrudes inward in a substantially horizontal direction from the inner surface of the cylindrical body 7b, an upward protruding portion 30 is formed concentrically with the cylindrical body 7b. The cross-sectional shape of the upward protruding portion 30 is not particularly limited, and for example, shapes such as a triangle, a semicircle, and an ellipse are preferred.

[0073] A gasket 21 serving as an O-ring is clamped between the lower surface 17 of the outer peripheral edge portion of the upper member 13 of the plug 12 and the side surface 20 of the outer peripheral wall 19 of the lower member 14 and the front end portion of the upward protruding portion 30. The gasket 21 serving as an O-ring is clamped and pressed by the outer peripheral edge portion 17 of the upper member 13 of the plug 12, the side surface 20 of the outer peripheral wall 19 of the lower member 14, and the front end portion of the upward protruding portion 30, and the mouth portion 5 is sealed.

[0074] In addition, in order to improve the sealing performance, when the gasket 21 serving as an O-ring and / or the upward protruding portion 30 is clamped and pressed by the lower surface 17 of the outer peripheral edge portion of the upper member 13 of the plug 12, the side surface 20 of the outer peripheral wall 19 of the lower member 14, and the front end portion of the upward protruding portion 30, compression deformation may also occur.

[0075] If the surface smoothness of the upward protruding portion 30, the lower surface 17 of the outer peripheral edge portion of the upper member 13, and the side surface 20 of the outer peripheral wall 19 of the lower member 14 with which the gasket 21 serving as an O-ring contacts becomes higher, the surface pressure applied to the surface of the gasket 21 is uneven, the close contact property is reduced, and the sealing performance is reduced. Therefore, the surface smoothness of the upward protruding portion 30, the lower surface 17 of the outer peripheral edge portion of the upper member 13, and the side surface 20 of the outer peripheral wall 19 of the lower member 14 is preferably 0.30 mm or less, more preferably 0.25 mm or less.

[0076] In addition, in order to improve the sealing performance, it is preferred that the center of the gasket 21 serving as an O-ring is located directly above the upward protruding portion 30. It is preferred that the surface smoothness of the surface of the upward protruding portion 30 is smaller, preferably 0.30 mm or less, more preferably 0.25 mm or less, and further preferably 0.20 mm or less. Moreover, the surface smoothness of the surface of the upward protruding portion 30 is preferably 0.05 mm or more smaller than the surface smoothness of the lower surface 17 of the outer peripheral edge portion of the upper member 13 and the surface of the gasket 21 serving as an O-ring.

[0077] Figure 9This is a cross-sectional view showing another different example of the state after closing the mouth of the plastic container of the present invention. On the upper surface of a substantially flat protruding portion 31 that protrudes inward in a substantially horizontal direction from the inner surface of the cylindrical body 7c, an upward protruding portion 32 is formed concentrically with the cylindrical body 7c. On the lower surface 17 of the outer peripheral edge portion of the upper member 13, a downward protruding portion 33 is formed concentrically with the cylindrical body 7c so as to be directly above the upward protruding portion 32. The cross-sectional shapes of the upward protruding portion 32 and the downward protruding portion 33 are not particularly limited, and for example, shapes such as a triangle, a semicircle, and an ellipse are preferred.

[0078] A gasket 21 in the form of an O-ring is clamped between the upward protruding portion 32 and the downward protruding portion 33, and the gasket 21 in the form of an O-ring is clamped and pressed by the front end portion of the upward protruding portion 32, the front end portion of the downward protruding portion 33, and the side surface 20 of the outer peripheral wall 19 of the lower member 14, and the mouth portion 5 is sealed.

[0079] In addition, in order to improve the sealing performance, when the gasket 21 in the form of an O-ring, the upward protruding portion 32, and / or the downward protruding portion 33 are clamped and pressed by the front end portion of the upward protruding portion 32, the front end portion of the downward protruding portion 33, and the side surface 20 of the outer peripheral wall 19 of the lower member 14, they may also undergo compressive deformation.

[0080] If the surface smoothness of the upward protruding portion 32 and the downward protruding portion 33 that the gasket 21 in the form of an O-ring contacts becomes high, the surface pressure applied to the surface of the gasket 21 is uneven, the close contact property decreases, and the sealing performance decreases. Therefore, the surface smoothness of the upward protruding portion 32 and the downward protruding portion 33 is preferably 0.30 mm or less, more preferably 0.25 mm or less, and further preferably 0.20 mm or less. Moreover, the surface smoothness of the upward protruding portion 32 and the downward protruding portion 33 is preferably 0.05 mm or more smaller than the surface smoothness of the surface of the gasket 21 in the form of an O-ring.

[0081] In order to improve the sealing performance, preferably, the upward protruding portion 32, the downward protruding portion 33, and the gasket 21 in the form of an O-ring are arranged such that the center of the gasket 21 in the form of an O-ring is directly above the upward protruding portion 32, and the downward protruding portion 33 is directly above the center of the gasket 21 in the form of an O-ring.

[0082] In addition, in Figure 8 it is also possible to form a protruding portion on the side surface 20 of the outer peripheral wall 19 of the lower member 14 and / or the inner surface 34 of the cylindrical body 7c facing inward. If such a protruding portion is formed, the gasket 21 in the form of an O-ring is clamped and pressed by more fulcrums, held more firmly, and the mouth portion of the plastic container is sealed more reliably. The cross-sectional shape of this protruding portion may be the same as that of the upward protruding portion 24.

[0083] And inFigure 8 In Figure 8 , if a protruding portion is formed on the inner surface 34 of the cylindrical body 7b so as to protrude inward, then by screwing the second threaded portion 16 formed on the side wall 15 of the plug 12 with the first threaded portion 8 formed on the inner surface of the cylindrical body 7b, the gasket 21 serving as an O-ring is clamped and pressed by four points, namely, the upward protruding portion 30, the side surface 20 of the outer peripheral wall 19 of the lower member 14, the lower surface 17 of the outer peripheral edge portion of the upper member 13, and the above-mentioned protruding portion, and the sealing property of the mouth portion of the plastic container is further improved.

[0084] In Figure 9 In Figure 9 , if a protruding portion is formed on the inner surface 35 of the cylindrical body 7c so as to protrude inward, then by screwing the second threaded portion 16 formed on the side wall 15 of the plug 12 with the first threaded portion 8 formed on the inner surface of the cylindrical body 7c, the gasket 21 serving as an O-ring is clamped and pressed by four points, namely, the upward protruding portion 32, the side surface 20 of the outer peripheral wall 19 of the lower member 14, the downward protruding portion 33, and the above-mentioned protruding portion, and the sealing property of the mouth portion of the plastic container is further improved.

[0085] Figure 10 is a cross-sectional view showing another different example of the state after closing the mouth portion of the plastic container of the present invention. Figure 10 And Figure 4 The difference from the structure shown in Figure 4 is that on the upper surface of the protruding portion 36 of the substantially flat cylindrical body 7d that protrudes inward in a substantially horizontal direction from the inner surface of the cylindrical body 7d, an obliquely upward protruding portion 37 is formed concentrically with the cylindrical body 7d. By screwing the second threaded portion 16 formed on the side wall 15 of the plug 12 with the first threaded portion 8 formed on the inner surface of the cylindrical body 7d, the gasket 21 serving as an O-ring is clamped, pressed, and firmly held by the lower surface 17 of the outer peripheral edge portion of the upper member 13, the side surface 20 of the outer peripheral wall 19 of the lower member 14, the obliquely upward protruding portion 37, the protruding portion 36, and the inner surface 38 of the cylindrical body 7d, and the mouth portion of the plastic container is more reliably sealed.

[0086] The plastic container of the present invention preferably has an identification information display portion provided at a position where it can be read from the outside of the container wall surface, and the identification information display portion can stick and peel a sheet that can be printed and updated, and the sheet is printed with identification information of the material of the container content.

[0087] The identification information display portion can be read from the outside of the container wall surface, is preferably flat, and is preferably provided on the upper wall portion or the side wall portion of the container so as to easily print and update the identification information of the material of the container content and easily stick and peel the sheet printed with the identification information of the material of the container content.

[0088] The upper wall or side wall of the plastic container can be directly used as the identification information display part. However, in the case where the plastic container is a transparent container, it is sometimes difficult to print and update the identification information, it is likely to peel off during the transportation of the container, and it is difficult to read from the outside. In addition, in the case of pasting a sheet printed with identification information, the pasting strength is sometimes weak and it falls off during transportation. Therefore, it is preferable that the identification information display part is colored, or subjected to matting treatment or corona treatment, and has unevenness and is opaque.

[0089] Any known method in the prior art can be adopted for printing and updating the identification information on the identification information display part, and it can also be handwritten. However, it is preferable to adopt a printing method such as laser printing or inkjet printing that can be managed by a computer.

[0090] In addition, in the case of printing the identification information on the identification information display part by laser printing or the like, since printing is carried out by using laser and accompanied by chemical reactions such as oxidation, it is preferable to use an olefin resin having a higher reactivity than polyethylene resin. In addition, it is preferable to add an inorganic pigment, an organic pigment, an inorganic filler, and other additives that are usually used in the manufacture of olefin resin containers to the outer layer.

[0091] In addition, as the sheet printed with the above-mentioned identification information, it is preferable to use an adhesive label, an adhesive sheet, etc. that are known in the prior art and have an adhesive layer laminated on one side of paper or a plastic sheet.

[0092] In addition, the above-mentioned identification information display unit is preferably a bar code, a two-dimensional code, a QR code (registered trademark), or an RF1D tag.

[0093] Industrial application fields

[0094] The plastic container of the present invention is lightweight, has high mechanical strength, excellent cleanliness, excellent leakage resistance of the content, and excellent airtightness. Therefore, it is suitable for use as a container for filling, storing, and transporting beverages and food liquids such as water, juice, and soy sauce; chemical products such as kerosene, acetic acid, hydrochloric acid, and nitric acid; high-viscosity and high-specific gravity solutions such as CMP slurries containing fillers with a high specific gravity such as abrasives, metal powders, and inorganic fillers; and medicines such as special industrial intermediates. In particular, it meets the UN standard during transportation and is suitable for use as a transportation container for high-viscosity and high-specific gravity solutions.

[0095] Explanation of reference numerals

[0096] 1 Container body

[0097] 2 Upper wall

[0098] 3 Side wall

[0099] 4 Bottom wall

[0100] 5 Mouth part

[0101] 6 Air inlet

[0102] 7, 7a, 7b, 7c, 7d Cylindrical bodies

[0103] 8 First threaded portion

[0104] 9 Inclined portion

[0105] 10 Protrusion

[0106] 11 Groove

[0107] 12 Plug

[0108] 13 Upper part

[0109] 14 Lower part

[0110] 15 Side wall

[0111] 16 Second threaded portion

[0112] 17 Lower surface of the outer peripheral edge portion

[0113] 18 Groove

[0114] 19, 19a Outer peripheral wall

[0115] 20, 20a Side surface

[0116] 21 Gasket

[0117] 22 Plastic cover

[0118] 23 Protrusion

[0119] 24 Upward protrusion

[0120] 25 Bulge

[0121] 26 Bulge

[0122] 27 Side surface

[0123] 28 Bulge

[0124] 29 Protrusion

[0125] 30 Upward protrusion

[0126] 31 Protrusion

[0127] 32 Upward protrusion

[0128] 33 Downward protrusion

[0129] 34 Inner surface

[0130] 35 Inner surface

[0131] 36 Protrusion

[0132] 37 Diagonal upward protrusion

[0133] 38 Inner surface.

Claims

1. A plastic container, comprising a container body having a mouth portion formed therein and a plug for closing the mouth portion, characterized in that, A first thread portion is formed on the inner surface of the above-mentioned mouth portion, a second thread portion capable of being threadedly engaged with the first thread portion is formed on the outer surface of the above-mentioned plug, a gasket is interposed between the outer surface of the above-mentioned plug and the inner surface of the mouth portion in a manner of abutting against the outer surface of the plug and the inner surface of the mouth portion, and in the plastic container, a raised portion is formed on the inner surface of the mouth portion in a manner of being able to contact the above-mentioned gasket.

2. The plastic container according to claim 1, wherein, A raised portion is formed below the second thread portion on the outer surface of the plug.

3. The plastic container according to claim 1, wherein A raised portion is formed below the first thread portion on the inner surface of the mouth portion.

4. The plastic container according to claim 2, wherein, A raised portion is formed below the first thread portion on the inner surface of the mouth portion.

5. The plastic container according to any one of claims 1 to 4, characterized in that, Grooves are respectively formed on the outer surface of the plug and the inner surface of the mouth portion at the portion where the gasket abuts.

6. The plastic container according to claim 5, wherein A protrusion is formed on the inner surface of the mouth portion at the portion where the gasket abuts.

7. The plastic container according to claim 5, characterized in that, A protrusion is formed on the outer surface of the plug at the portion where the gasket abuts.

8. The plastic container according to claim 6, characterized in that, A protrusion is formed on the outer surface of the plug at the portion where the gasket abuts.

9. The plastic container according to claim 8, characterized in that, The gasket is an O-ring.

10. The plastic container according to claim 9, wherein, A lid covers the mouth portion.

11. The plastic container according to claim 10, wherein, The roundness of the mouth portion is 1.0 mm or less.

Images