JPH1182745A - Sealing member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing member which easily compresses and deforms by receiving load, is quick in a shape recovery after load is removed and is difficult to generate compression permanent distortion even if the sealing member receives load of some degrees. SOLUTION: This sealing member 1 made of foam plastic is buried into an annular groove provided near the surrounding on the rear side of the cover of a fiber drum. The sealing member 1 has a long size and is provided with a hollow part 3 extending in the longitudinal direction. When the cover of the fiber drum is placed on a main body, the volume of the hollow part 3 is reduced by gravity of the cover and the sealing member 1 compresses and deforms. The sectional form of the sealing member 1 is a roughly semi-circular shape. In the part corresponding to the chord of this cross section, a recessed part 2 extending in the longitudinal direction is provided. When the cover is placed on the main body, this recessed part 2 envelops the upper part of the main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal member provided at, for example, a contact portion between a main body of a fiber drum and a lid.

[0002]

[Prior Art] Pharmaceuticals, industrial materials, building materials, building materials,
BACKGROUND ART Fiber drums are used as packaging containers for packing paints and the like when transporting, storing, displaying, and the like.
This fiber drum is composed of a main body and a lid. If the medicine or the like to be packed easily absorbs moisture, it is necessary to seal the space between the main body and the lid in order to avoid the moisture absorption. In the fiber drum, a long sealing member is embedded in an annular groove provided on the back side (main body side) of the lid near the outer periphery, and when the lid is placed on the main body, this sealing member is placed on the upper part of the main body. By being brought into contact with the upper end of the base, the space between the main body and the lid is sealed.

Conventionally, rubber, foamed or non-foamed plastic made long by extrusion and the like have been used as the seal member, and the plastic material is polyethylene, polypropylene, polyamide, polyvinyl chloride, or the like. (For example, Japanese Patent Publication No. 2-332)
No. 98, JP-A-1-247137, etc.).

[0004]

Since the sealing member made of rubber or plastic is not flexible enough, even when the lid is placed on the main body, the sealing performance is not sufficiently achieved by the weight of the lid alone. Not demonstrated. In addition, the lid floats by the thickness of the seal member, and it is difficult to stably mount the lid.

[0005] By increasing the expansion ratio by using foamed plastic, it is also possible to obtain a seal member which has improved flexibility and exhibits sealing performance only by its own weight of the lid. For example, in the case of a sealing member made of foamed polyethylene, if the foaming ratio is set to 20 times or more, compression deformation easily occurs, and the lid can be stably installed.

However, the sealing member having a high expansion ratio has a low elastic recovery rate, and it takes a long time for the sealing member to recover its original shape even if the lid is removed after the lid has been placed on the main body for a long time. When the fiber drum is reused immediately, there is a problem that the sealing performance is not sufficiently exhibited. In addition, a plurality of fiber drums are often stored in a stack, and when a sealing member having a high expansion ratio is used for a lower fiber drum of the stack, the sealing member is stacked above the fiber drum or the inside of the fiber drum. Under the load of the package, compression set may be caused. A sealing member that has undergone compression set has a problem that the sealing performance when reused is extremely reduced.

The present invention has been made in view of the above-mentioned problems, and is easily compressed and deformed by receiving a load.
It is an object of the present invention to provide a seal member that recovers its shape quickly after removing a load and is less likely to cause compression set even under a certain load.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a long-sized sealing member made of plastic containing air bubbles.
A sealing member having a hollow portion extending in the longitudinal direction (claim 1).

According to the present invention, since the hollow portion is provided inside the seal member, the volume of the hollow portion is reduced when a load is applied to the seal member, so that the seal member can be easily compressed and deformed. Can be obtained. Therefore, it is not necessary to increase the foaming ratio so much, the elastic after-effect is reduced, the shape restoring force is increased, and even when a certain load is applied, compression set is hardly caused.

[0010] In the present invention, if the volume of the hollow portion is set to 10% or more and 70% or less of the volume of the sealing member, it is possible to more easily achieve both compressive deformation and strength (claim 2).

In the present invention, the sealing member is embedded in a lid of a container such as a fiber drum by making the cross-sectional shape of the sealing member in a direction perpendicular to the longitudinal direction substantially semicircular (claim 3). When used, the part corresponding to the semicircular string can be brought into contact with the main body base,
The lid can be more stably installed on the main body. In particular, if a concave portion extending in the longitudinal direction is formed in a portion corresponding to the string (claim 4), the concave portion can wrap the upper end portion of the base, and the cover can be more stably mounted on the main body.

[0012] As a plastic used for the seal member, a plastic having an ethylene vinyl alcohol resin as a main polymer, which has a large elastic modulus and excellent rigidity as compared with a polyolefin resin such as polyethylene and polypropylene, is used. Permanent distortion can be further suppressed (claim 5). This ethylene vinyl alcohol resin is excellent in mechanical strength, abrasion resistance and gas barrier properties, and is therefore suitable for use as a sealing member for applications that require a load, such as a fiber drum.

Further, even if a plastic mainly composed of a thermoplastic elastomer having excellent restoring force is used as the plastic used for the seal member, the compression set of the seal member can be further suppressed. 6).

In the case of using a plastic whose main polymer is an ethylene vinyl alcohol resin or a thermoplastic elastomer, the expansion ratio is preferably 1.2 times or more and 5.0 times or less (claim 7). By setting the expansion ratio in this range, it becomes possible to more easily achieve both the ease of compressive deformation when receiving a load and the shape recovery force after removing the load.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail by taking a case where the present invention is applied to a fiber drum as an example with reference to the drawings as appropriate.

FIG. 1A is a perspective view of a seal member 1 according to an embodiment of the present invention, and FIG.
Shows a cross-sectional view in the longitudinal direction and the vertical direction. The seal member 1 is made of foamed plastic and has a long shape as shown in FIG.
Further, as shown in FIG. 1B, the cross-sectional shape in the longitudinal direction and the vertical direction is substantially semicircular. A concave portion 2 extending in the longitudinal direction is provided at a portion corresponding to a chord of a semicircular cross section. Further, a hollow portion 3 extending in the longitudinal direction is provided inside the seal member 1.

FIGS. 2 (a) and 2 (b) show FIGS.
A fiber drum using the sealing member 1 shown in (b) is shown. FIG. 2A is a vertical cross-sectional view of the fiber drum, and FIG.
It is an enlarged view of A part shown by the dotted circle in (a). In FIG. 2A, the seal member 1 is omitted for convenience.

The fiber drum comprises a main body 4 and a lid 5
And The main body 4 has a cylindrical body 6 made of laminated kraft paper or the like, an annular base 7 made of steel and provided at an upper end of the body 6, and a lower end of the body 6 made of steel. An annular bottom metal 8 provided;
A bottom plate 9 made of laminated kraft paper or the like and stretched inside a bottom metal 8 is provided. The lid 5 has a disk shape,
It is composed of steel. Back side of lid 5 (body 4 side)
An annular groove 10 is provided in the vicinity of the outer periphery. The vertical cross section of the groove 10 is substantially semicircular. The material constituting the fiber drum is not limited to the above. For example, the body 6 and the bottom plate 9 may be formed of a plywood, a hard board, or the like, and the base 7, the bottom metal 8, and the lid 5 may be formed of a copper alloy, an aluminum alloy, or the like.

To attach the seal member 1 to the fiber drum, the seal member 1 is embedded in the groove 10 of the lid 5. Upon embedding, the seal member 1 is curved in an annular shape so that both ends thereof abut. As described above, the cross-sectional shape of the seal member 1 in the longitudinal direction and the vertical direction is substantially semicircular, and when the seal member 1 is embedded in the groove 10, a portion corresponding to the arc of the cross-sectional shape of the seal member 1 is formed. It comes into contact with the inner periphery of the groove 10.

When the lid 5 is placed on the main body 4, the portion corresponding to the chord of the cross-sectional shape of the seal member 1 abuts on the upper end of the base 7 of the main body 4. Since the concave portion 2 is formed in the seal member 1, the upper end of the base 7 is wrapped by the concave portion 2, and the lid 5 can be more stably installed on the main body 4. Of course, when the lid 5 can be sufficiently stably installed on the main body 4 without providing the recess 2, the recess 2 is omitted.

When the lid 5 is placed on the main body 4, the lid 5
Due to its own weight, the seal member 1 is subjected to a vertically downward load. When the volume of the hollow portion 3 is reduced by the load, the seal member 1 is easily compressed and deformed.
In this way, the lid 5 is stably installed on the main body 4 without being lifted from the main body 4.

The volume of the hollow portion 3 is preferably from 10% to 70%, more preferably from 20% to 40% of the volume of the sealing member 1. If the volume of the hollow portion 3 is less than the above range, sufficient compression deformation may not be caused by the weight of the lid 5 alone. Conversely, if the volume of the hollow portion 3 exceeds the above range, the thickness of the seal member 1 may be too small, and the elastic recovery force of the seal member 1 may be reduced.

As described above, in the seal member 1, since the compression deformation of the entire seal member 1 is achieved by the reduction in the volume of the hollow portion 3, it is not necessary to use a material having a very high deformability. In this seal member 1, an ethylene vinyl alcohol resin having high rigidity is used, and the expansion ratio (the ratio of the density in the absence of air bubbles to the density in the presence of air bubbles) is set to twice the relatively low magnification. I have. By using plastic having high rigidity and having a low expansion ratio in this manner, the shape recovery of the sealing member 1 when the lid 5 is removed (that is, when the load is removed) can be accelerated, Further, it is possible to prevent permanent compression set when a certain high load is applied.

In place of the ethylene vinyl alcohol resin,
Even when using a thermoplastic elastomer with excellent elastic restoring force,
The shape recovery of the sealing member 1 when the lid 5 is removed can be accelerated, and the permanent compression set when a certain high load is applied can be prevented. Examples of the thermoplastic elastomer used include styrene-based thermoplastic elastomer, polyolefin-based thermoplastic elastomer, polyvinyl chloride-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, 1,2-polybutadiene-based thermoplastic elastomer, and trans. Examples include a polyisoprene-based thermoplastic elastomer, a fluororubber-based thermoplastic elastomer, a chlorinated polyethylene-based thermoplastic elastomer, and a dynamically crosslinked thermoplastic elastomer.

When a plastic having the above-mentioned ethylene vinyl alcohol resin or thermoplastic elastomer as a main polymer is used for the sealing member 1, its expansion ratio is 1.2.
It is preferably at least 1.5 times and not more than 5.0 times, particularly preferably at least 1.5 times and not more than 3.0 times. If the expansion ratio is less than the above range, no matter how the hollow portion 3 is provided, the compression deformation may not be caused only by the own weight of the lid 5. Conversely, if the expansion ratio exceeds the above range, the shape recovery force when the load is removed may be inferior, or when a high load is applied, permanent compression may be caused.

In addition to the above-mentioned ethylene vinyl alcohol resin and thermoplastic elastomer, for example, polyethylene, polypropylene, polyvinyl chloride and the like can be used as main polymers. When these plastics are used, the expansion ratio may be appropriately adjusted in consideration of the rigidity of the resin.

Since the sealing member 1 is embedded in the groove 10 having a substantially semicircular cross section, the cross section is also substantially semicircular. However, the cross sectional shape of the sealing member 1 is limited to a substantially semicircular shape. Instead, if the shape of the groove 10 to be buried changes, it is changed accordingly. Further, even when the sealing member 1 is used for an application other than the fiber drum, the cross-sectional shape of the sealing member 1 can be set to, for example, a circle or a rectangle according to the application.

The cells of the seal member 1 may be open cells or closed cells, but closed cells are preferred for obtaining better gas barrier properties. Bubbles are generally formed by using a foaming agent. The blowing agent used may be a low-boiling type blowing agent or a thermal decomposition type chemical blowing agent. In particular, it is preferable to use a low-boiling type foaming agent because foaming is completed instantaneously and is suitable for mass production. Examples of such low-boiling type blowing agents include aliphatic hydrocarbons such as propane, butane and pentane, chlorinated aliphatic hydrocarbons such as methylene chloride and methyl chloride, and inorganic compounds such as freon, nitrogen and carbon dioxide. Gas and the like.

The plastic used for the sealing member 1 may contain a coloring agent, a foaming assistant, a stabilizer, a plasticizer, a weathering agent, a deterioration inhibitor, a processing aid, etc., as required, in addition to the above-mentioned foaming agent. An appropriate amount is blended.

Although the present invention has been described by taking a fiber drum as an example, the seal member of the present invention can be applied to various containers such as an open drum, and other applications that require airtightness other than containers. It can be applied to all.

[0031]

As described above, according to the present invention,
It is possible to provide a seal member that easily undergoes compressive deformation by receiving a load, quickly recovers its shape after removing the load, and hardly causes compression set even when a certain amount of load is received.

[Brief description of the drawings]

FIG. 1A is a perspective view showing a seal member according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view of the seal member.

FIG. 2A is a sectional view of a fiber drum using the seal member shown in FIGS. 1A and 1B, and FIG. 2B is a partially enlarged view of the fiber drum; It is sectional drawing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Seal member 2 ... Concave part 3 ... Hollow part 4 ... Body 5 ... Lid 6 ... Body part 7 ... Base 8 ... Bottom metal 9 ... Bottom plate 10 ... groove

Claims (7)

[Claims] 1. A sealing member made of plastic containing air bubbles and having a long shape, wherein a sealing member having a hollow portion extending in a longitudinal direction is provided therein. 2. The volume of the hollow portion is one of the volume of the sealing member.
The seal member according to claim 1, wherein the content is 0% or more and 70% or less. 3. The seal member according to claim 1, wherein a cross-sectional shape in a direction perpendicular to the longitudinal direction is substantially semicircular. 4. A cross section in a direction perpendicular to the longitudinal direction is substantially semicircular, and a portion corresponding to a chord of the semicircle includes:
The seal member according to claim 3, wherein a concave portion extending in the longitudinal direction is formed. 5. The seal member according to claim 1, wherein the plastic is a plastic having an ethylene vinyl alcohol resin as a main polymer. 6. The plastic according to claim 1, wherein said plastic is a thermoplastic elastomer-based polymer.
5. The sealing member according to any one of items 1 to 4. 7. The sealing member according to claim 5, wherein the expansion ratio is 1.2 times or more and 5.0 times or less.