JPH10245066A - Sealing structure of synthetic resin container and sealing gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing structure of a synthetic resin container in which the structure is simplified and a gasket can be easily mounted to the structure and a self-sealing function can be produced against the difference between inner and outer pressures of a container and the impact on the container so that sealing characteristics can be always ensured. SOLUTION: A gasket fitting groove 22 is formed along the inner or outer circumferential wall surface of an open end portion 21 of a bottom case body 20, and a cover body 50 comprising an outer fitting wall portion 53 which has an L-shaped cross section formed along the peripheral edge of an open end portion 51 so as to be opposed to the upper end surface of the end 21 and the groove 22 is fitted on the open end 21 through a ring gasket 70 fitted in the groove 22 so as to be tightly fixed. Desirably, the case body 20 and the cover body 50 are made of materials having different rigidities. Even if a difference in pressure is produced between the inner and outer sides of a container 10 so that the bodies 20, 50 are deformed so as to be spaced apart one from the other, the gasket 70 is pressed between the end portions 21, 51 and at the same time the portions 21, 51 slide relative to each other so that the gasket 70 is not separated from the end portions, whereby a complete seal is always maintained utilizing the deformation of the container.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing structure and a gasket for a container with a lid which hermetically seals a container with a lid made of a synthetic resin which is easily deformed by a pressure difference between the inside and the outside via a gasket. A sealed structure of a synthetic resin container, which effectively shields easily fragile and extremely polluting articles from outside air, etc., and always secures sealing properties by utilizing the deformation of the container based on changes in external pressure. The present invention relates to a gasket suitable for application to a closed structure.

[0002]

2. Description of the Related Art A typical example of a container with a lid comprising a case body and a lid molded from a synthetic resin material used for storing and transporting easily fragile and contaminated articles is disclosed in There is a packaging container for transporting semiconductor wafers disclosed in Japanese Patent Application Laid-Open No. 5-63067. A general packaging container of this type includes a wafer carrier for accommodating a plurality of semiconductor wafers, a bottom case body for accommodating and holding the wafer carrier, a lid, and a wafer pressing member. As a general material of the wafer carrier and the bottom case, polypropylene is used, and the lid is made of polypropylene or polycarbonate. The wafer pressing member is made of polypropylene, polyester or polyethylene.

[0003] The semiconductor wafer is manufactured by thinly slicing a single crystal such as silicon. The semiconductor wafer is highly brittle and has a great influence on physical properties due to contamination. Every effort must be made to prevent it. The semiconductor wafer packaging container not only prevents the wafer from being damaged due to an external impact, but also causes contamination by particles generated by friction with the wafer pressing member in the container, and the outside air due to deformation of the container due to a difference in internal and external pressure. To avoid intrusion and contamination, ensure the stability of wafer support during storage and prevent contact friction with the wafer pressing member, etc., and at the same time, the toughness and impact resistance of the container body consisting of the bottom case and lid It is strictly required to ensure airtightness and airtightness.

For this reason, the bottom case body has conventionally been provided with a substantially inverted U-shape with the open side edge of the bottom case body 2 outward as shown in FIG. 9 and disclosed in Japanese Patent Laid-Open No. 5-63065. It is formed into a bent shape to give rigidity to the open-side edge 1a, which is most susceptible to deformation and breakage, to strengthen the structure, and to provide a gasket fitting groove in the upper end surface of the edge of the case body 2. A rib-shaped projection 4 having an outer periphery 3 is provided, and an outer fitting end 5a on the open side of one lid 5 has a groove 6 for accommodating a part of the gasket 7 and its cross section is formed in a substantially L-shape. And the gasket fitting groove 3 of the case body 2
The gasket 7 is fitted between the gasket 7 and the groove 6 of the lid 5, and the outer fitting end 5 a of the lid 5 is fitted externally to the rib-like projection 4 of the bottom case body 2. The container 1 is hermetically closed by being fixedly fixed by a fixing portion (not shown).

[0005]

However, in the case of the packaging container 1 made of synthetic resin for semiconductor wafers, the container 1
After the semiconductor wafer is stored, the cover is easily lifted by an external impact during transportation or during storage, or the cover is easily deformed so as to be lifted by the internal pressure with a change in the outside air pressure. For example, when the container 1 is transported by air, the pressure difference between the inside and the outside of the container reaches 0.2 to 0.25 atm, and the amount of deformation is between the bottom case 2 and the lid 5 by the sealing of the gasket. The air is so large that a small gap is generated to the extent that the performance is lost, and even outside air entering through such a small gap causes fatal contamination to the semiconductor wafer in the container. As described above, in a case where an article that is extremely contaminated by contamination so that all of various processes performed thereafter are performed in a clean room, the above-described situation immediately leads to a loss of commercial value of the article. Therefore, it is an essential requirement for this type of container to ensure its hermetic sealing function. In order to ensure this, the structure is usually adopted to increase rigidity by adopting the above-described structure.

However, in the case of a synthetic resin container,
No matter what material is used, the deformation cannot be avoided unless the thickness is extremely increased. However, an increase in the thickness leads not only to an increase in the amount of resin used but also to an increase in the size of the container. On the other hand, as described above, if the open end portions of the bottom case body 2 and the lid body 5 that are most likely to be affected by the external environment and are easily deformed are structurally stiffened, the form is inevitably complicated, and the number of molding dies increases. And the cavity shape becomes complicated, the molding operation becomes complicated, and the molding cost greatly increases.

The present invention has been made to solve these problems, and specifically utilizes the ease of deformation of a synthetic resin container, and in particular, the deformation of a case body and a lid due to a pressure difference between inside and outside. The purpose of the present invention is to provide a closed structure of a synthetic resin container having a simple configuration that ensures a complete sealing performance by exerting a self-sealing function.

[0008]

In order to achieve the above object, the sealed structure of the synthetic resin container according to the first aspect of the present invention is a sealed structure in which a case body and a lid are hermetically sealed via a gasket. A gasket fitting groove formed along any one of inner and outer peripheries of the open end of the case main body, an annular gasket fitted into the gasket fitting groove, and an open end of the lid. It is characterized by comprising a fitting wall portion formed along a peripheral edge and having a substantially L-shaped cross section facing the end surface of the open end of the case body and the gasket fitting groove.

In this type of conventional sealing structure, since the upper end surface of the open end of the case body and the lower surface of the open end of the lid are simply sealed via a gasket, the case is temporarily provisioned by a clamper. Even if the fitting between the main body and the lid is firmly fixed, the case and the lid move in the separating direction, for example, the lid is lifted from the case main body, or the case body and / or the part other than the fixing part by the clamper. The lid was deformed and a gap was easily formed between the two.

On the other hand, according to the configuration of the present invention, for example, when the atmospheric pressure is reduced to become lower than the internal pressure of the container, the case main body and the lid are bulged outward. At the same time as the case body is deformed, the fitted wall portion of the cover body slides on the gasket of the case body at a portion other than the clamp portion of the case body, and the lid body tries to float up in the direction away from the case body. However, in the present invention, the size of the peripheral side surface is set so that the gasket is kept in close contact with the gasket from either side inside or outside the fitted wall portion of the lid even during the deformation. The sealing function of the gasket is not lost.

According to the second aspect of the present invention, the gasket fitting groove is formed over the entire circumference of the end surface of the open end of the case body or the lid, or the inside and outside thereof, and the gasket fitting groove is formed in the gasket fitting groove. An annular gasket is fitted, and a rib-like projection extending continuously to the inside of the gasket fitting groove along the periphery of the open end of the other lid or case body facing the gasket fitting groove is continuously projected. Let me. Even in the sealed structure of the present invention, for example, when the atmospheric pressure is reduced and becomes lower than the internal pressure of the container, the case body and the lid are deformed so as to bulge outward, and at the same time, the case body and The lid is deformed in the separating direction. At this time, in the present invention, when the protrusion on the rib moves away from the gasket in response to the movement of the case body and the lid in the direction of separation, the gasket expands its cross section in an attempt to return to its original shape. Also, against deformation swelling outward of the case body and lid,
The tip of the rib-shaped projection slides while being in close contact with the gasket, thereby ensuring the sealing performance.

The most preferable configuration for these inventions is a case where a difference in rigidity is provided between at least the open ends of the case body and the lid. That is, as an aspect, the rigidity of the open end of the case body is set higher than the rigidity of the open end of the lid, and the gasket fitting groove is formed on the inner wall surface of the open end of the case. When the outer wall surface of the fitted wall portion of the lid is opposed to the gasket fitting groove, the rigidity of the open end of the case body is set lower than the rigidity of the open end of the lid, A gasket fitting groove is formed on the outer wall surface of the open end of the case body, and an inner wall surface of the fitted wall portion of the lid may face the gasket fitting groove. In addition, a gasket fitting groove is formed on the entire upper end surface of the open end of the case body.

In the case of employing such a configuration, since there is a difference in rigidity between the case body and the lid body, the smaller the rigidity, the greater the deformation and the more effective the sealing function described above. Become. In all of the above-mentioned closed structures, the thickness of the gasket in the depth direction of the gasket fitting groove of the case body is determined by the case body based on the internal / external pressure difference during transportation of the container as in the third aspect of the present invention. When changing in accordance with the distribution of the amount of deformation of the lid, the sealing function is further improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below more specifically with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing a closed structure of a synthetic resin container as a typical embodiment according to the first invention. The following description refers to a semiconductor wafer packaging container as an example of the container. However, the present invention is not limited to this, and it is highly brittle and can be used for articles that do not want to come into contact with outside air or chemicals. It can be applied to packaging containers. The wafer packaging container is used by hermetically storing the wafer carrier when storing, moving, and transporting a large number of semiconductor wafers that are neatly accommodated and supported by the wafer carrier.

First, a conventional general hermetic structure in a semiconductor wafer packaging container will be described with reference to FIGS. 7 to 9. Usually, the wafer packaging container 1 is composed of a bottom case 2, a lid 5, The bottom case body 2 has an inner surface shape such that a wafer carrier (not shown) can be housed therein in a fitted state. The lid 5 is fitted to the bottom case 2 from the outside, and is fixedly fastened by a fastening means such as a clamper 8. Bottom case 2
9 and each open end of the lid 5 has a substantially rectangular frame shape.
A substantially inverted L-shaped extending portion 5b is formed outwardly from the edge of the outer fitting end 5a of the lid 5 so that each open end thereof is shown in a cross section of the main part. A rib-like projection 5c projecting substantially vertically downward from the protrusion 5c. A groove 6 is formed between the extending portion 5b and the rib-like projection 5c over the entire circumference of the lid 5.

On the other hand, the structure of the open end of the bottom case body 2 is formed by bending the open end outward in a substantially inverted U-shape as shown in FIG. In addition to providing rigidity to the open-side edge 2a, which is easy to perform, the structure is strengthened, and a gasket-fitting groove 3 is formed all around the upper end surface of the edge of the case body 2, and the gasket-fit is formed. A rib-shaped projection 4 is provided along the groove 3. Prior to packaging, the gasket fitting groove 3 has a gasket 7
Is fitted. Usually, the cross-sectional shape of the gasket 7 has a shape in which fin-shaped flaps are extended from both ends of an oblong long diameter portion.

In the packaging container 1 having such a configuration, after a wafer carrier (not shown) is stored in the bottom case body 2,
The cover 5 is fitted outside. At this time, the upper exposed end of the gasket 7 fitted in the gasket fitting groove 3 of the bottom case body 2 fits into the groove 6 of the lid 5 and the bottom part is clamped by the clamper 8 as shown in FIG. The case 2 and the lid 5 are engaged and fixed, and the space between the bottom case 2 and the lid 5 is hermetically sealed.

In many cases, the packaging container 1 thus sealed is carried out from a semiconductor wafer manufacturing factory, and is transported by air to a device manufacturing factory. During the transportation or transportation, an unexpected impact may occur. In particular, as described above, the air pressure fluctuates greatly during the air transportation, and generally, the pressure inside and outside the packaging container 1 is increased.
A pressure difference of more than twice occurs. Due to such impact and pressure difference, an extremely large load is applied to the bottom case body 2 and the lid body 5 from the inside to the outside as shown by arrows X and Y in FIG. The corner 11, which is the most easily deformable portion, may significantly deform the bottom case body 2 and the lid body 5 in the separating direction, and a small gap may be generated to such an extent that the sealing function of the gasket is lost. When such deformation is repeated, even if there is a pressure difference, outside air easily enters through the gap,
The outside air comes into contact with the semiconductor wafer housed inside. This exposure to outside air is sufficient to contaminate the wafer and lose commercial value.

On the other hand, in the present invention, as schematically shown in FIG. 1 as a first embodiment, the open end 21 of the bottom case body 20 is set to a minimum necessary thickness and the outer peripheral portion thereof is A gasket fitting groove 22 is formed along the surface, and a gasket 70 is fitted in the gasket fitting groove 22. The open end 51 of one lid 50 is connected to the bottom case 2
The outer fitting end 53 is formed by extending outward from the side wall 52 of the lid 50 having a rectangular frame shape in an inverted L-shape so as to be fitted from the outside to the open end 21 of the “0”. I do. Since the illustrated example is schematically illustrated to explain the basic principle of the present invention, other specific configurations necessary for further improving the sealing performance are omitted from the drawings, but the technical field is well-known. Those skilled in the art can easily understand from the basic structure shown in the figure that various changes and additions in the configuration are possible.

Now, the pressure inside the container becomes higher than the outside air pressure, and as shown by arrows X and Y in FIG.
When a large internal pressure is applied to the entire lid 50, the lid 50
The outer fitting end 53 of which the outer fitting end 53 is in close contact with the gasket 70
3 strongly presses the open end 21 of the bottom case body 20 outward in the X direction. At this time, simultaneously, pressure in the Y direction acts on all the inner wall surfaces of the bottom case body 20 and the lid body 50. In this case, when both the bottom case body 20 and the lid 50 are made of the same material, the open end 21 of the bottom case body 20 and the outer fitting end 53 of the lid 50 are formed.
Is deformed in the X direction, and as the pressure in the Y direction becomes farther from the mechanically engaged portion of the bottom case body 20 and the lid body 50 by a clamper or the like, the bottom case body 20 and the lid body 50 are moved away from each other. And acts to greatly deform. If the wall surface of the outer fitting end portion 53 of the outer fitting end portion 53 of the lid body 50 that is in close contact with the gasket 70 is set to a sufficient width in consideration of the amount of deformation at this time, even during the deformation. Since the outer fitting end 53 is in close contact with the gasket 70, the sealing performance is reliably maintained. That is, in the synthetic resin container 10 in which elastic deformation, which has been regarded as a drawback in the past, cannot be avoided, the present invention is intended to enhance the sealing function by effectively utilizing the characteristics of the material. ,
Therefore, the installation site of the gasket 70 is brought to the side surface of the open end of the container 10 as described above.

FIG. 2 shows a modification of the first embodiment. The technical principle is the same as that of the first embodiment. In this modification, the outer fitting end 53a of the lid 50 is provided. Is fitted to the inner wall surface of the open end 21 of the bottom case body 20. In this case, when the material of both the bottom case body 20 and the lid body 50 is the same, the open end 21 of the bottom case body 20 and the outer fitting end 5 of the lid body 50 are formed.
3a, the outer fitting end 53a of the lid 50 tends to deform more than the deformation of the open end 21 of the bottom case body 20 based on the thickness difference, so that the gasket 70 is stronger than before deformation. It compresses and further improves the sealing performance as compared with the above embodiment.

FIGS. 3 and 4 show a second embodiment of the present invention corresponding to the first embodiment and its modification. In addition to the constitution of the first embodiment and its modification, respectively, FIG. Open end 21 of case body 20 and outer fitting end 5 of lid body 50
3a, the gasket 70 extends over the entire area around the upper end of the bottom case body 20, that is, the portion where the gasket 3a faces vertically.
A second gasket fitting groove 23 for fitting the second gasket 71 is formed separately from the second gasket 71. In this way, by fitting the second gasket 71 to the open upper end surface of the bottom case body 20, even when the external air pressure becomes larger than the internal pressure of the container, the second gasket 71 is connected to the open end 21 of the bottom case body 20. Since the sealing function is complemented by both the outer fitting ends 53 and 53a of the lid 50, it is possible to cope with all aspects of the pressure difference between the inside and the outside of the container 10. Although the two gaskets 70 and 71 are separately formed in the illustrated example, the gaskets 70 and 71 may be formed so as to be connected by a strip having an L-shaped cross section made of the same material. it can.

FIG. 5 shows a third embodiment of the present invention based on the same technical idea as the first and second embodiments. According to FIG. A gasket fitting groove 23 corresponding to the above-described second gasket fitting groove 23 is formed on the open upper end surface, and the entire periphery of the wall surface of the outer fitting end 53 of the lid 50 facing the gasket fitting groove 23 is formed. When the cover 50 is fitted through the gasket 70 to the outside, a rib-like projection 54 having a dimension to penetrate into the gasket fitting groove 23 is provided.

When the bottom case body 20 and the lid body 50 are deformed in the directions indicated by arrows X and Y in FIG.
Since the movement in the direction and the corresponding deformation of the gasket 70 follow well, the sealing function of the gasket 70 is not lost. In addition, in this embodiment, since the rib-shaped protrusion 54 is sufficiently digged, the gasket 70 can be formed into a simple oval cross section without having a special cross-sectional shape as shown in FIG. In this case, the fitting operation into the gasket fitting groove 23 becomes easy.

Conversely, in the first and second embodiments shown in FIGS. 1 to 4 and their modifications, if the materials used for the bottom case body 20 and the lid body 50 are further made different, The above-mentioned sealing performance is further improved. That is, for example, in the embodiment shown in FIG. 1, a resin material having higher rigidity than the rigidity of the bottom case body 20 is used for the lid body 50. By doing so, not only the difference in the amount of deformation based on the thickness difference between the open end 21 of the bottom case body 20 and the outer fitting end 53 of the lid 50 can be reduced, but also the difference in rigidity can be increased. For example, the open end 21 of the bottom case body 20
Is larger than that of the outer fitting end 53 of the lid 50 and the amount of compression of the gasket 70 is increased, so that the sealing function is further enhanced. This is the same in the embodiment shown in FIG. 2, but in this case, the rigidity of the bottom case body 20 and the lid body 50 is selected from the former which is less rigid than the latter.

FIG. 6 shows a gasket form particularly suitable for application to the embodiments and modifications shown in FIGS. That is, the gasket configuration shown in FIG. 6 is an example of a gasket configuration suitable for use in fitting into the gasket fitting groove 23 formed on the open upper end surface of the bottom case body 20. However, since the gasket fitting groove 23 is formed in the same location as that of the conventional gasket, this gasket form can be applied to the conventional gasket fitting groove. Therefore, the usage of the gasket form is limited. It is not intended to be performed, but is included in the present invention.

As described above, when a pressure difference between the inside and outside occurs in the container 10, the deformation of the bottom case body 20 and the lid body 50 from the part fixed by the fixing means such as the clamper as the distance from the part increases. The amount increases. Usually, the amount of deformation at the corners of the bottom case body 20 and the lid body 50 is the largest. FIG. 6 shows a gasket configuration suitable for being applied to a normal container structure. Although the figure is shown as a schematic diagram in which the dimensional difference is extremely large for easy understanding, the actual fluctuation value is numerically much smaller.

Normally, the clamper is provided substantially at the center between the corners 11 of the rectangular box-shaped container 10 as shown in FIG. Accordingly, in the illustrated example, the thickness of the gasket 71 corresponding to the installation portion of the clamper is made thinnest, and the thickness is gradually increased toward each corner 11. With this configuration, even when the inner pressure of the container 10 greatly exceeds the external pressure and the corner portion 11 is largely deformed, the lid 50 and the gasket 71 are separated from each other to form a gap. Disappears, ensuring the sealing function of the gasket.

As can be understood from the above description, the present invention can be variously modified. For example, the embodiment shown in FIGS. 1 to 4 and the modified example can be combined with the embodiment door shown in FIG. The gasket configuration shown in FIG. 6 can be variously combined.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view schematically illustrating a closed structure of a bottom case body and a lid body according to a first embodiment of the present invention.

FIG. 2 is a partial sectional view showing a modification of the embodiment.

FIG. 3 is a partial cross-sectional view schematically showing a closed structure of a bottom case body and a lid body according to a second embodiment of the present invention.

FIG. 4 is a partial sectional view showing a modification of the embodiment.

FIG. 5 is a partial sectional view schematically showing a closed structure of a bottom case body and a lid body according to a second embodiment of the present invention.

FIG. 6 is a perspective view schematically showing a preferred embodiment of a gasket applied to the present invention.

FIG. 7 is an overall perspective view schematically showing an example of a general semiconductor wafer packaging container.

FIG. 8 is an enlarged view of a portion A in FIG. 7 when the packaging container is deformed.

FIG. 9 is a partial cross-sectional view showing an example of a conventional general closed structure of a bottom case body and a lid body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Semiconductor wafer packaging container 20 Bottom case body 21 Open end 22, 23 Gasket fitting groove 50 Lid 51 Open end 52 Side wall 53, 53a External fitting end 54 Rib-shaped projection 70, 71 Gasket

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masao Kikuchi 1200 Manda, Hiratsuka-shi, Kanagawa Prefecture, Komatsu Ltd.

Claims (7)

[Claims] 1. A sealed structure of a synthetic resin container in which a case body and a lid are hermetically sealed via a gasket, wherein the case body and the lid are formed along one of inner and outer peripheries of an open end of the case body. A gasket fitting groove; an annular gasket fitted in the gasket fitting groove; and an end face of the open end of the case body formed along a periphery of an open end of the lid and the gasket fit. A hermetically sealed structure for a synthetic resin container, comprising: a fitting wall portion having a substantially L-shaped cross section facing each of the grooves. 2. The hermetically sealed structure according to claim 1, wherein a gasket fitting groove is formed on the entire end surface of the open end of the case body. 3. A closed structure of a synthetic resin container in which a case main body and a lid are hermetically sealed via a gasket, wherein the case main body or the lid has an open end or an inner or outer surface. A gasket fitting groove formed over the circumference, an annular gasket fitted in the gasket fitting groove, and a peripheral edge of the open end of the opposing lid or case body facing the gasket fitting groove. A hermetically sealed structure for a synthetic resin container, comprising: a rib-shaped projection continuously projecting and extending to the inside of the gasket fitting groove. 4. The sealed structure according to claim 1, wherein a rigidity difference is provided between at least open ends of the case body and the lid. 5. The rigidity of the open end of the case body is set higher than the rigidity of the open end of the lid, and the gasket fitting groove is formed on the inner wall surface of the open end of the case. 5. The sealed structure according to claim 4, wherein an outer wall surface of the fitted wall portion of the lid faces the gasket fitting groove. 6. The rigidity of the open end of the case body is set lower than the rigidity of the open end of the lid, and the gasket fitting groove is formed on the outer wall surface of the open end of the case body. 5. The sealed structure according to claim 4, wherein an inner wall surface of the fitted wall portion of the lid faces the gasket fitting groove. 7. A gasket applied to any one of the container sealing structures according to claim 1, wherein a thickness of the gasket fitting groove of the case main body of the gasket in a depth direction of the container is set to a thickness of the container. A sealing gasket, which is changed in accordance with a distribution of deformation of the case body and the lid body based on a pressure difference between inside and outside during transportation.