TW202423801A - Plastic drum - Google Patents

Abstract

Provided is a plastic container that is lightweight, has excellent environmental friendliness and leak prevention properties, and has excellent sealing properties during storage and transportation. In particular, the plastic container is suited to holding, storing, and transporting high-density, high-viscosity solutions such as CMP slurries, and meets UN specifications. A first screw portion 8 is formed in an inner surface of a cylindrical body 7. A second screw portion 16 capable of screwing into the first screw portion 8 is formed on an outer surface of a top member 13 of a plug 12. A gasket 21 is interposed between an outer surface of the plug 12 and an inner surface of an opening 5 so as to abut the outer surface of the plug 12 and the inner surface of the opening 5. A protrusion 25 is formed in the inner surface of the opening 5 in a manner allowing contact with the gasket 21.

Description

Plastic Containers

The present invention relates to a plastic container which is suitable for filling, storing and transporting solutions such as CMP slurry and meets UN specifications.

Paper containers, glass containers, metal containers, plastic containers, etc. have been widely used for storage and transportation due to their required container performance such as lightness, mechanical strength, and cleanliness.

In recent years, along with the development of the industry, high-viscosity solutions such as high-viscosity foods, chemical solutions, CMP slurries, photoresists, and developers are widely filled in containers for storage, transportation, and industrial use. Such high-viscosity solutions have high specific gravity and are heavy, and are generally discharged through dispensers, so containers are required to have high mechanical strength.

Therefore, various proposals have been made in the industry as containers for the above-mentioned high-viscosity solutions. For example, it is described in Patent Document 1 that, as shown in the cross-sectional view of FIG. 11, "a barrel mouth portion 41 has an inner thread 42, which is threadably engaged with a plug 44 having an outer thread 43, a washer 45 is disposed below the thread, and a sealing surface is formed by a protruding end surface 46 of the barrel mouth portion 41 and a horizontal end surface 47 of the plug 44, and two annular protrusions 48a and 48b are formed on the outer periphery of the barrel mouth portion 41, as shown in the cross-sectional view of FIG. 12, When the dustproof cover 49 is installed, the protrusion 48 is engaged with the protrusion 50 of the dustproof cover 49 to serve as an anti-detachment member, as shown in the cross-sectional view of FIG13. When the safety sealing cover 51 is installed, the protrusion 48a is engaged with the protrusion 52 of the sealing cover 51 to serve as an anti-detachment member, as shown in the cross-sectional view of FIG11. The upper end surface 53 of the barrel mouth 41 is a mouth plug portion of the resin barrel located at a position higher than the upper end surface 56 of the L-shaped ring 55 of the resin barrel 54 and located at a position lower than the barrel top surface 57. ".

The mouth plug of the resin barrel is provided with a gasket 45 between the resin barrel 54 and the plug 44. On the other hand, since high-viscosity solutions such as CMP slurry contain fillers with high specific gravity such as abrasives, metal powders, and inorganic fillers, the fillers precipitate during storage and transportation and cannot be used directly. For this reason, the resin barrel is supplied to a rotating device or a vibrating device before use, and the high-viscosity solution is uniformly stirred by rotation or vibration before use. However, only by providing the gasket 45, there is a disadvantage that the high-viscosity solution leaks out during rotation or vibration. [Prior technical literature] [Patent literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 11-342962

[The problem the invention is trying to solve]

In view of the above problems, the purpose 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 during storage and transportation, especially a plastic container that is suitable for filling, storing and transporting high-density and high-viscosity solutions such as CMP slurry, and meets UN specifications. [Technical means to solve the problem]

The plastic container of the first invention of the present invention application for achieving the above-mentioned purpose comprises a container body having a mouth and a plug for sealing the mouth, and a first threaded portion is formed on the inner surface of the mouth, a second threaded portion that can be screwed into the first threaded portion is formed on the outer surface of the plug, and a gasket is interposed between the outer surface of the plug and the inner surface of the mouth in a manner that abuts against the outer surface of the plug and the inner surface of the mouth. The plastic container is characterized in that a ridge is formed on the inner surface of the mouth in a manner that can contact the gasket. The plastic container of the second invention of the present invention application is the same as the first invention of the present invention application, wherein a ridge is formed below the second threaded portion on the outer surface of the plug. The plastic container of the third invention of the present invention application is as described in the first invention of the present invention application, wherein a ridge is formed below the first threaded portion on the inner surface of the mouth. The plastic container of the fourth invention of the present invention application is as described in the second invention of the present invention application, wherein a ridge is formed below the first threaded portion on the inner surface of the mouth. The plastic container of the fifth invention of the present invention application is as described in any one of the first to fourth inventions of the present invention application, wherein grooves are formed on the outer surface of the plug and the inner surface of the mouth at the portion where the gasket abuts. The plastic container of the sixth invention of the present invention application is as described in the fifth invention of the present invention application, wherein a protrusion is formed on the inner surface of the mouth at the portion where the gasket abuts. The plastic container of the seventh invention of the present invention application is as described in the fifth invention of the present invention application, wherein a protrusion is formed on the outer surface of the plug at the portion where the gasket abuts. The plastic container of the eighth invention of the present invention application is as described in the sixth invention of the present invention application, wherein a protrusion is formed on the outer surface of the plug at the portion where the gasket abuts. The plastic container of the ninth invention of the present invention application is as described in the eighth invention of the present invention application, wherein the gasket is an O-ring. The plastic container of the tenth invention of the present invention application is as described in the ninth invention of the present invention application, wherein a lid is sealed at the mouth. The plastic container of the eleventh invention of the present invention application is as described in the tenth invention of the present invention application, wherein the roundness of the mouth is less than 1.0 mm. [Effect of the invention]

The structure of the plastic container of the present invention is as described above, light weight, high mechanical strength, high cleanliness and airtightness, excellent leakage resistance of the contents, excellent sealing during storage and transportation, and is particularly suitable for filling, storage and transportation of high-density and high-viscosity solutions such as CMP slurry.

The plastic container of the first invention of the present invention application comprises a container body formed with a mouth, and a plug for sealing the above-mentioned mouth, and a first threaded portion is formed on the inner surface of the above-mentioned mouth, and a second threaded portion that can be screwed into the first threaded portion is formed on the outer surface of the above-mentioned plug, and a gasket is interposed between the outer surface of the above-mentioned 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, and is characterized in that a bulge is formed on the inner surface of the above-mentioned mouth in a manner that can contact the above-mentioned gasket.

The shape of the plastic container is not particularly limited, and is preferably substantially cylindrical, barrel-shaped, or prism-shaped. The plastic container is preferably made of plastic.

The plastic is any known resin that has been used as a material for liquid containers, such as natural resins, thermoplastic resins, and thermosetting resins. Preferably, it is a thermoplastic resin with excellent thermoformability, high mechanical strength, and excellent cleanliness, and olefin resins are preferred.

The above-mentioned olefin resin is a polymer obtained by polymerizing olefin monomers such as ethylene monomers and propylene monomers as main raw materials, for example, ethylene homopolymers such as high-density polyethylene resins, medium-density polyethylene resins, and low-density polyethylene resins; copolymers of ethylene as the main component and α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, and 1-heptene; homopolymer polypropylene resins, random Propylene homopolymers such as polypropylene resins, copolymers mainly composed of propylene and α-olefins such as ethylene, 1-butene, 1-hexene, 1-pentene, and 1-heptene, etc., preferably high-density polyethylene resins, medium-density polyethylene resins, homopolymer polypropylene resins, and random polypropylene resins for obtaining containers with high mechanical strength and excellent self-supporting properties, and more preferably high-density polyethylene resins and polypropylene resins. In addition, these olefin resins may be used alone or in combination of two or more olefin resins.

Next, the plastic container of the present invention is described with reference to the drawings. In addition, in each of the drawings, the same or identical components are given the same symbols.

FIG. 1(A) is a side view showing an example of a plastic container of the present invention, and FIG. 1(B) is a top view thereof. In FIG. 1(A), 1 is a barrel-shaped container body including an upper wall portion 2, a side wall portion 3, and a bottom wall portion 4, and a mouth portion 5 and an air port 6 are formed on the upper wall portion 2. The air port 6 is an opening portion that is used to inject air when discharging the stored liquid so as not to reduce the pressure in the container and reduce the discharge speed of the stored liquid, or to connect to a pressurizing device in order to set the container to a pressurized state for the purpose of easily discharging the stored liquid. Needless to say, the air port 6 is closed when the container body 1 is filled with the stored liquid and stored and transported. In addition, a plurality of air ports 6 may be provided. The structure of the air port 6 is not particularly limited, and it may be a simple opening or a cylindrical shape, or may be the same shape as the port in the invention of the present application.

The manufacturing method of the container body is not particularly limited. When the container body is made of olefin resin, the olefin resin is preferably formed by blow molding. As the blow molding method, any blow molding method known in the art may be used, for example, extrusion blow molding, injection blow molding, stretch blow molding, multi-layer blow molding, etc.

FIG. 2 is a cross-sectional view showing an example of the mouth 5 formed on the container body 1 of the above-mentioned plastic container. The mouth 5 has a cylindrical body 7 located above the upper wall 2 of the container body 1, and can inject and discharge the storage liquid. A first threaded portion 8 is formed near the upper portion of the inner surface of the cylindrical body 7, and a generally flat protrusion 10 is formed below the first threaded portion 8, which is protruded inwardly along a generally horizontal direction through an inclined portion 9. Furthermore, the front end of the protrusion 10 faces downward in the vertical direction, and its lowermost end is connected to the upper wall 2 to form the mouth 5. A groove 11 with a generally arc-shaped cross section is formed on the upper surface of the protrusion 10, and a part of the O-ring, i.e., the gasket, described later, can be embedded in the groove 11 slightly recessed inwardly from the upper surface of the protrusion 10.

FIG. 3(A) is a cross-sectional view showing an example of a stopper 12 in a plastic container of the present invention, and FIG. 3(B) is a bottom view thereof. The stopper 12 includes a circular plate-shaped upper member 13 and a circular plate-shaped lower member 14. The diameter of the upper member 13 is longer than the diameter of the lower member 14, and the upper member 13 and the lower member 14 are concentrically stacked and integrally formed. In addition, a rib for reinforcement is vertically provided on the side surface of the upper member 13 to form a side wall 15, and a second threaded portion 16 is formed on the side wall 15, and the second threaded portion 16 can be screwed into the first threaded 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 portion of the upper component 13. A portion of an O-ring or gasket to be described later can be embedded in the groove 18 which is slightly recessed inward from the lower surface 17 of the outer peripheral portion.

FIG4 is a cross-sectional view showing an example of a state where the mouth of the plastic container of the present invention is sealed. The second threaded portion 16 formed on the side wall 15 of the upper member 13 of the plug 12 is screwed into the first threaded portion 8 formed on the inner surface of the cylindrical body 7. By screwing the second threaded portion 16 into the first threaded portion 8, the O-ring, i.e., the gasket 21, 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 portion of the O-ring, i.e., the gasket 21, is embedded in the grooves 11 and 18. Thus, since the gasket 21 contacts the outer surface of the plug 12 and the inner surface of the mouth 5 at four locations and is clamped and pressed, the mouth 5 can ensure excellent sealing. By forming the gasket 21 with plastic material, the gasket 21 is sometimes compressed and deformed when being clamped and pressed. In order to improve the sealing performance, it is preferred that the inner diameter of the gasket 21 is the same as or slightly smaller than the outer diameter of the lower component 14. As long as a portion of the gasket 21 can be embedded in 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 component 14.

Reference numeral 22 is a plastic cover, which is sealed to protect and strengthen the sealed mouth 5. For example, the cover 22 may be a structure that covers the mouth 5 by pressing and is 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 5, a threaded portion that can be screwed into the threaded portion th may be formed on the inner surface of the cover 22.

If the cylindrical body 7 is deformed and not a true circle, the sealing property is reduced, leakage may occur, or the plug may fall off, so the plane shape of the cylindrical body 7 is preferably a true circle. That is, the higher the roundness of the cylindrical body 7, the better, more preferably less than 1.0 mm, and particularly preferably less than 0.8 mm.

The roundness of the present invention is the difference between the length of the major diameter and the length of the minor diameter of the upper surface of the cylindrical body 7, and the unit is mm. In addition, if the plastic container is manufactured by blow molding, it will become an ellipse with the PL (parting line) direction as the major axis, so the length of the PL direction and the direction perpendicular to it can be measured, and the difference is set as the roundness. The smaller the difference, the higher the roundness.

Since the second threaded portion 16 formed on the side wall 15 of the upper member 13 is screwed into the first threaded portion 8 formed on the inner surface of the cylindrical body 7, if the upper member 13 is deformed and not a true circle, the sealing property cannot be ensured. Therefore, the sealing property is reduced, and sometimes leakage or the plug 12 may fall off. Therefore, the plane shape of the upper member 13 is preferably a true circle. That is, the higher the roundness of the upper member 13, the better, more preferably less than 1.0 mm, and particularly preferably less than 0.8 mm.

In this specification, the O-ring is a solid or hollow annular body, and its cross-sectional shape is not particularly limited, for example, circular, elliptical, quadrilateral, hexagonal, etc., but preferably circular, because the circular shape will not fatigue over time and will not deform. Therefore, the O-ring is preferably a solid or hollow annular body with a circular cross-sectional shape.

By screwing the second threaded portion 16 into the first threaded portion 8, a portion of the O-ring, i.e., the gasket 21, is embedded in the groove 11 and the groove 18, and the gasket 21 contacts, is clamped and pressed against the outer surface of the plug 12 and the inner surface of the mouth 5 at four locations, thereby ensuring excellent sealing of the mouth 5. Therefore, if the O-ring, i.e., the gasket 21, is too hard, the toughness is reduced, and the sealing performance is easily reduced over time; if it is too soft, it is easy to fatigue, or the wear resistance is reduced, thereby reducing the sealing performance. For this reason, the hardness (durometer D) of the gasket 21 is preferably 40 to 48. In addition, in the invention of this application, the hardness (durometer D) is a value measured in accordance with JIS K 7215-1986.

Because an O-ring, i.e., a gasket 21, is clamped between the upper surface of the protrusion 10 protruding toward the inner surface of the cylindrical body 7 and the lower surface 17 of the outer peripheral portion of the upper component 13 of the plug 12, the sealing performance of the container body 1 is improved, and the upper surface of the protrusion 10 and the lower surface 17 of the outer peripheral portion of the upper component 13 are preferably approximately horizontal and parallel.

An O-ring or gasket 21 is sandwiched between the upper surface of the protrusion 10 protruding toward the inner surface of the cylindrical body 7 and the lower surface 17 of the outer peripheral portion of the upper component 13 of the plug 12. In order to improve the sealing performance of the container body 1, the protrusion 10, the upper component 13 and the O-ring or gasket 21 are preferably in closer contact.

If the surface smoothness of the upper surface of the protrusion 10 connected to the O-ring or gasket 21 and the lower surface 17 of the outer peripheral portion of the upper component 13 becomes higher, the surface pressure applied to the surface of the O-ring or gasket 21 becomes uneven, and the sealing performance is reduced. Therefore, the smaller the above-mentioned surface smoothness, the better.

Therefore, the surface smoothness of the upper surface of the protrusion 10 and the lower surface 17 of the outer peripheral portion of the upper member 13 is preferably 0.30 mm or less, more preferably 0.25 mm or less. In addition, for the same reason, the surface smoothness of the surface of the gasket 21 is also preferably 0.30 mm or less, more preferably 0.25 mm or less.

Furthermore, since the O-ring, i.e., the gasket 21, is located on the upper surface of the protrusion 10 on the inner surface of the cylindrical body 7, in order to improve the sealing performance, the surface smoothness of the upper surface of the protrusion 10 is preferably smaller, preferably less than 0.20 mm, and the surface smoothness of the upper surface of the protrusion 10 is preferably at least 0.05 mm smaller than the surface smoothness of the lower surface 17 of the outer peripheral portion of the upper component 13 and the surface of the gasket 21.

In addition, the "surface smoothness" in the present invention is a value measured by a three-dimensional measuring instrument (manufactured by Mitutoyo Corporation of Japan, trade name "QUICK VISION PRO").

If, as described above, a groove (11, 18) having a circular arc-shaped cross-sectional shape into which a portion of an O-ring, i.e., a gasket 21, is formed on the upper surface of the protrusion 10 formed on the inner surface of the cylindrical body 7 and/or the lower surface 17 of the outer peripheral portion of the upper component 13 of the plug 12, then when the first threaded portion 8 formed on the inner surface of the cylindrical body 7 and the second threaded portion 16 formed on the side wall 15 of the plug 12 are screwed together, the plug 12 and the O-ring, i.e., the gasket 21 are more strongly in close contact, and the sealing performance is improved, which is preferred.

Furthermore, for the same reason, a groove having a circular arc-shaped cross-section into which a portion of an O-ring, i.e., a gasket 21, can be embedded can be formed on the side surface 20 of the outer peripheral wall 19 of the lower component 14 of the plug 12.

The material constituting the above-mentioned plug 12 and gasket 21 is preferably olefin resin, and more preferably high-density polyethylene resin or polypropylene resin. When the above-mentioned plug 12 and O-ring, i.e., gasket 21, are made of olefin resin, it is preferably formed by injection molding.

Fig. 5 is a cross-sectional view showing a different example of the state in which the mouth of the plastic container of the present invention is sealed. The second threaded portion 16 formed on the side wall 15 of the upper member 13 of the plug 12 is screwed into the first threaded portion 8 formed on the inner surface of the cylindrical body 7a.

The O-ring or gasket 21 is fitted to 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 generally flat plate-shaped protrusion 23 protruding inwardly in a generally horizontal direction from the inner surface of the cylindrical body 7a, an upward protrusion 24 is formed concentrically with the cylindrical body 7a, and the cylindrical body 7a is formed with a protrusion 25 protruding inwardly as it shrinks downward.

In addition, the upward protrusion 24 only needs to be formed upward concentrically with the cylindrical body 7a on the upper surface of the protrusion 23, and its position is not particularly limited. It is preferably formed on the upper surface of the protrusion 23 between the center of the O-ring, i.e., the gasket 21, and the side surface 20 of the outer peripheral wall 19 of the lower component 14.

The cross-sectional shape of the upward protrusion 24 is not particularly limited, and is preferably triangular, semicircular, elliptical, etc. In order to improve the sealing performance, the O-ring or gasket 21 and/or the upward protrusion 24 can be compressed and deformed when the O-ring or gasket 21 abuts against the front end of the upward protrusion 24, the ridge 25, the lower surface 17 of the outer peripheral portion of the upper component 13, and the side surface 20 of the outer peripheral wall 19 of the lower component 14 to be clamped and pressed.

By screwing the second threaded portion 16 formed on the side wall 15 of the plug 12 into the first threaded portion 8 formed on the inner surface of the cylindrical body 7a, the O-ring, i.e., the gasket 21, is clamped and pressed by the lower surface 17 of the outer peripheral portion of the upper component 13 of the plug 12, the side surface 20 of the outer peripheral wall 19 of the lower component 14, the front end of the upward protrusion 24 and the raised portion 25, and the mouth 5 is sealed.

The O-ring, i.e., gasket 21, is held by the raised portion 25, and the surface smoothness of the raised portion 25 is preferably less than 0.30 mm, more preferably less than 0.25 mm, and particularly preferably less than 0.20 mm. The surface smoothness of the raised portion 25 is preferably at least 0.05 mm less than the surface smoothness of the O-ring, i.e., gasket 19.

Furthermore, a protrusion may be formed on any one of the lower surface 17 of the outer peripheral 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 O-ring, i.e., the gasket 21, is clamped and pressed by more fulcrums, so that it is more firmly held, and the container body 1 is more securely sealed. The cross-sectional shape of the protrusion may be the same as that of the upward protrusion 24.

Furthermore, as shown in FIG. 6(A), a raised portion 26 may be provided on the side surface 20a of the outer peripheral wall 19a of the lower member 14, and as shown in FIG. 6(B), a raised portion 28 may be provided on the side surface 27 of the protruding portion 23. By providing such raised portions 26 and 28, the following effects can be expected. That is, since the gasket 21 is installed on the plug 12 after being installed on the mouth 5, if the gasket 21 is screwed in a state where it is not installed in an appropriate position, the surface of the mouth 5 or the surface of the plug 12 may be damaged, or the first threaded portion 8 or the second threaded portion 16 may be deformed. For this purpose, the ridges 26 and 28 are provided 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, so that the gasket 21 can be easily positioned and installed at 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 threaded portion 8 and the second threaded portion 16 are not deformed. Therefore, the storage liquid does not leak and the plug 12 does not fall off. It is sufficient to provide either the ridges 26 or 28 on the plastic container of the present invention. Needless to say, both the ridges 26 and 28 can be provided on the same plastic container.

The gap d1 between the front end of the raised portion 26 and the protrusion 23 as shown in Figure 7(A) and the gap d2 between the front end of the raised portion 28 and the outer peripheral wall 19 of the lower component 14 as shown in Figure 7(B) are preferably less than 1 mm, more preferably less than 0.05 mm, and the lower limit of the gaps d1 and d2 is 0.01 mm.

FIG8 is a cross-sectional view showing another different example of the state in which the mouth of the plastic container of the present invention is sealed. On the upper surface of the generally flat protrusion 29 protruding inwardly from the inner surface of the cylindrical body 7b in a generally horizontal direction, an upward protrusion 30 is formed concentrically with the cylindrical body 7b. The cross-sectional shape of the upward protrusion 30 is not particularly limited, and is preferably triangular, semicircular, elliptical, etc.

An O-ring or gasket 21 is clamped between the upward protrusion 30 and the lower surface 17 of the outer peripheral portion of the upper component 13 of the plug 12 and the side surface 20 of the outer peripheral wall 19 of the lower component 14. The O-ring or gasket 21 is clamped and pressed by the outer peripheral portion 17 of the upper component 13 of the plug 12, the side surface 20 of the outer peripheral wall 19 of the lower component 14 and the front end of the upward protrusion 30, and the mouth 5 is sealed.

In addition, in order to improve the sealing performance, the O-ring, i.e., the gasket 21 and/or the upward protrusion 30 can be compressed and deformed when clamped and pressed by the lower surface 17 of the outer peripheral portion of the upper component 13 of the plug 12, the side surface 20 of the outer peripheral wall 19 of the lower component 14 and the front end of the upward protrusion 30.

If the surface smoothness of the upward protrusion 30 connected to the O-ring, i.e. the gasket 21, the lower surface 17 of the outer peripheral portion of the upper component 13, and the side surface 20 of the outer peripheral wall 19 of the lower component 14 becomes higher, the surface pressure applied to the surface of the gasket 21 becomes uneven, the adhesion is reduced, and the sealing performance is reduced. Therefore, the surface smoothness of the upward protrusion 30, the lower surface 17 of the outer peripheral portion of the upper component 13, and the side surface 20 of the outer peripheral wall 19 of the lower component 14 is preferably less than 0.30 mm, and more preferably less than 0.25 mm.

Furthermore, in order to improve the sealing performance, it is preferred that the center of the O-ring, i.e., the gasket 21, is located directly above the upward protrusion 30, and the surface smoothness of the surface of the upward protrusion 30 is preferably smaller, preferably less than 0.30 mm, more preferably less than 0.25 mm, and particularly preferably less than 0.20 mm, and the surface smoothness of the surface of the upward protrusion 30 is preferably less than the surface smoothness of the lower surface 17 of the outer peripheral portion of the upper component 13 and the surface of the O-ring, i.e., the gasket 21 by at least 0.05 mm.

FIG9 is a cross-sectional view showing another different example of the state in which the mouth of the plastic container of the present invention is sealed. An upward protrusion 32 is formed concentrically with the cylindrical body 7c on the upper surface of a generally flat protrusion 31 protruding inwardly from the inner surface of the cylindrical body 7c in a generally horizontal direction, and a downward protrusion 33 is formed concentrically with the cylindrical body 7c on the lower surface 17 of the outer peripheral portion of the upper member 13 so as to be located directly above the upward protrusion 32. The cross-sectional shapes of the upward protrusion 32 and the downward protrusion 33 are not particularly limited, and are preferably triangular, semicircular, elliptical, or the like.

An O-ring or gasket 21 is clamped between the upward protrusion 32 and the downward protrusion 33. The O-ring or gasket 21 is clamped and pressed by the front end of the upward protrusion 32, the front end of the downward protrusion 33 and the side surface 20 of the outer peripheral wall 19 of the lower component 14, and the mouth 5 is sealed.

In addition, in order to improve the sealing performance, the O-ring, i.e., the gasket 21, the upward protrusion 32 and/or the downward protrusion 33 can be compressed and deformed when clamped and pressed by the front end of the upward protrusion 32, the front end of the downward protrusion 33 and the side surface 20 of the outer peripheral wall 19 of the lower component 14.

If the surface smoothness of the upward protrusion 32 and the downward protrusion 33 connected to the O-ring, i.e., the gasket 21, becomes higher, the surface pressure applied to the surface of the gasket 21 becomes uneven, the adhesion is reduced, and the sealing performance is reduced. Therefore, the surface smoothness of the upward protrusion 32 and the downward protrusion 33 is preferably less than 0.30 mm, more preferably less than 0.25 mm, and even more preferably less than 0.20 mm, and the surface smoothness of the upward protrusion 32 and the downward protrusion 33 is preferably less than the surface smoothness of the surface of the O-ring, i.e., the gasket 21 by at least 0.05 mm.

In order to improve the sealing performance, it is better to configure the upward protrusion 32, the downward protrusion 33 and the O-ring or gasket 21 in such a way that the center of the O-ring or gasket 21 is located directly above the upward protrusion 32 and the downward protrusion 33 is located directly above the center of the O-ring or gasket 21.

In addition, in FIG8 , a protrusion may be formed inwardly 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. If such a protrusion is formed, the O-ring, i.e., the gasket 21, is clamped and pressed by more fulcrums, thereby being more firmly held and the mouth of the plastic container is more securely sealed. The cross-sectional shape of the protrusion may be the same as that of the upward protrusion 24.

Furthermore, in FIG. 8 , if a protrusion is formed on the inner surface 34 of the cylindrical body 7b in an inwardly protruding manner, the second threaded portion 16 formed on the side wall 15 of the plug 12 is screwed into the first threaded portion 8 formed on the inner surface of the cylindrical body 7b, and the O-ring, i.e., the gasket 21 is clamped and pressed at four points, namely, the upward protrusion 30, the side surface 20 of the outer peripheral wall 19 of the lower component 14, the lower surface 17 of the outer peripheral portion of the upper component 13, and the above-mentioned protrusion, thereby further improving the sealing performance of the mouth of the plastic container.

In FIG. 9 , if a protrusion is formed on the inner surface 35 of the cylindrical body 7c so as to protrude inward, by screwing the second threaded portion 16 formed on the side wall 15 of the plug 12 into the first threaded portion 8 formed on the inner surface of the cylindrical body 7c, the O-ring, i.e., the gasket 21, is clamped and pressed at four points, namely, the upward protrusion 32, the side surface 20 of the outer peripheral wall 19 of the lower component 14, the downward protrusion 33, and the above-mentioned protrusion, thereby further improving the sealing performance of the mouth of the plastic container.

Fig. 10 is a cross-sectional view showing another different example of the state in which the mouth of the plastic container of the present invention is sealed. Fig. 10 is different from the structure shown in Fig. 4 in that an oblique upward protrusion 37 is formed concentrically with the cylindrical body 7d on the upper surface of the protrusion 36 of the cylindrical body 7d which is substantially flat and protrudes inwardly in a substantially horizontal direction from the inner surface of the cylindrical body 7d. By screwing the second threaded portion 16 formed on the side wall 15 of the plug 12 into the first threaded portion 8 formed on the inner surface of the cylindrical body 7d, the O-ring, i.e., the gasket 21, is gripped and pressed by the lower surface 17 of the outer peripheral portion of the upper component 13, the side surface 20 of the outer peripheral wall 19 of the lower component 14, the oblique upward protrusion 37, the protrusion 36 and the inner surface 38 of the cylindrical body 7d, and is firmly held, thereby more securely sealing the mouth of the plastic container.

The plastic container of the present invention is preferably provided with an identification information display portion at a position that can be read from the outside of the container wall, and the identification information display portion can attach and peel off a sheet printed with identification information of the material of the container contents and capable of printing and updating.

The identification information display portion can be read from the outside of the container wall, and in order to easily print and update the identification information of the material of the container contents, and to easily attach and peel off the sheet printed with the identification information of the material of the container contents, it is preferably flat and preferably arranged on the upper wall or side wall of the container.

The upper wall or side wall of the plastic container can be directly used as the identification information display part, but in the case of a transparent plastic container, it is sometimes difficult to print and update the identification information, and it is not easy to peel off during the transportation of the container and difficult to read from the outside. In addition, when a sheet with printed identification information is attached, the attachment strength is sometimes weak and it falls off during transportation. Therefore, it is better to color the identification information display part, or apply matte processing or corona treatment, and have concave and convex and be opaque.

The method for printing and updating the identification information on the identification information display unit can adopt any previously known method, which can be handwritten, but preferably a printing method that can be managed by a computer, such as laser printing, inkjet printing, etc.

Furthermore, when the identification information is printed on the identification information display portion by laser printing or the like, since the printing is performed by laser accompanied by chemical reactions such as oxidation, it is preferable to use an olefin resin having a higher reactivity than polyethylene resin. Furthermore, it is preferable to add inorganic pigments, organic pigments, inorganic fillers and other additives generally used in the manufacture of olefin resin containers to the outer layer.

Furthermore, as the sheet printed with the above-mentioned identification information, it is preferable to use a previously known adhesive label or adhesive sheet made by laminating an adhesive on one side of a paper or plastic sheet.

Furthermore, the identification information display mechanism is preferably a barcode, a two-dimensional code, a QR code (registered trademark) or an RFID tag. [Industrial application areas]

The plastic container of the present invention is lightweight, has high mechanical strength, excellent cleanliness, excellent leakage resistance of the contents, and excellent airtightness, so it is suitable for use as a container for filling, storing, and transporting water, juice, soy sauce and other beverages, drinking and edible liquids, kerosene, acetic acid, hydrochloric acid, nitric acid and other chemicals, CMP slurry containing abrasives, metal powders, inorganic fillers and other high-specific gravity fillers and other high-viscosity, high-specific gravity solutions, special industrial intermediates and other drugs. In particular, it meets the UN specifications for transportation and is suitable for use as a transport container for high-viscosity, high-specific gravity solutions.

1: Container body 2: Upper wall 3: Side wall 4: Bottom wall 5: Mouth 6: Air port 7,7a,7b,7c,7d: Cylindrical body 8: First threaded portion 9: Inclined portion 9a,34,35,38: Inner surface 10,23,29,31,36: Protrusion 11,18: Groove 12,44: Plug 13: Upper member 14: Lower member 15: Side wall 16: Second threaded portion 17: Lower surface of outer peripheral portion 19,19a: Outer peripheral wall 20,20a,27: Side surface 21: Gasket 22: Plastic cover 24,30,32: Upward protrusion 25,26,28: Bump 33: Downward protrusion 37: Oblique upward protrusion 41: Barrel mouth 42: Internal thread 43: External thread 45: Gasket 46: Protrusion end surface 47: Horizontal end surface 48a,48b,50,52: Protrusion 49: Dustproof cover 51: Sealing cover 53,56: Upper end surface 54: Resin barrel 55: L-shaped ring 57: Barrel top surface d1,d2: Gap

FIG. 1(A) is a side view showing an example of a plastic container of the present invention, and FIG. 1(B) is a top view thereof. FIG. 2 is a cross-sectional view showing an example of a mouth portion of a plastic container of the present invention. FIG. 3(A) is a cross-sectional view showing an example of a stopper of a plastic container of the present invention, and FIG. 3(B) is a bottom view thereof. FIG. 4 is a cross-sectional view showing an example of a state where the mouth portion of the plastic container of the present invention is sealed. FIG. 5 is a cross-sectional view showing a different example of a state where the mouth portion of the plastic container of the present invention is sealed. FIG. 6(A) and FIG. 6(B) are cross-sectional views showing another different example of a state where the mouth portion of the plastic container of the present invention is sealed. Fig. 7 (A) and Fig. 7 (B) are diagrams for explaining the gap between the raised portion and the opposing member. Fig. 8 is a cross-sectional view showing another different example of the state in which the mouth of the plastic container of the present invention is sealed. Fig. 9 is a cross-sectional view showing another different example of the state in which the mouth of the plastic container of the present invention is sealed. Fig. 10 is a cross-sectional view showing yet another example of the state in which the mouth of the plastic container of the present invention is sealed. Fig. 11 is a partial cross-sectional view showing the details of the mouth plug of the resin barrel described in Patent Document 1. Fig. 12 is a cross-sectional view showing the state in which a dustproof cap is installed on the mouth plug of the resin barrel described in Patent Document 1. FIG. 13 is a cross-sectional view showing a state where a safety sealing cap is installed on the mouth plug of the resin barrel described in Patent Document 1.

1: Container body

2: Upper wall

5: Mouth

7a: Cylindrical body

8: 1st thread part

12: Plug

13: Upper components

14: Lower components

16: Second thread section

17: Surface below the outer edge

19: Outer wall

20: Side

21: Gasket

22: Plastic cover

23: Protrusion

24: Upward protrusion

25: Raised part

Claims (11)

A plastic container includes a container body formed with a mouth, and a plug for sealing the mouth, wherein a first threaded portion is formed on the inner surface of the mouth, a second threaded portion that can be screwed into the first threaded portion is formed on the outer surface of the plug, and a gasket is interposed between the outer surface of the plug and the inner surface of the mouth in a manner that abuts 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 that can contact the gasket. A plastic container as claimed in claim 1, wherein a raised portion is formed below the second threaded portion on the outer surface of the stopper. A plastic container as claimed in claim 1, wherein a raised portion is formed below the first threaded portion on the inner surface of the mouth. A plastic container as claimed in claim 2, wherein a raised portion is formed below the first threaded portion on the inner surface of the mouth. A plastic container as claimed in any one of claims 1 to 4, wherein grooves are formed on the outer surface of the stopper and the inner surface of the mouth at the portion where the gasket abuts. As in claim 5, a plastic container has a protrusion formed on the inner surface of the mouth where the gasket abuts. A plastic container as claimed in claim 5, wherein a protrusion is formed on the outer surface of the plug at the position where the gasket abuts. A plastic container as claimed in claim 6, wherein a protrusion is formed on the outer surface of the plug at the position where the gasket abuts. A plastic container as claimed in claim 8, wherein the gasket is an O-ring. A plastic container as claimed in claim 9, wherein the mouth is sealed with a lid. For example, in the plastic container of claim 10, the roundness of the mouth is less than 1.0 mm.