MXPA01003931A - Container assembly and bottom cap therefor - Google Patents

Abstract

A container (20) with an open end (34) and a bottom cap (52). The bottom cap (52) has a sealant material (60) bonded thereto to provide a hermetic seal between the bottom cap and the open bottom of the container and a grip surface (62) through or slightly beyond the exterior surface of the bottom cap.

Description

ASSEMBLY OF CONTAINER AND LOWER COVER FOR THE SAME BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container having an open bottom, and a bottom lid for sealing and sealing the open bottom. More particularly, the present invention is directed to such a container and lower lid in which the lower lid has a sealing material bonded thereto to form the hermetic seal. Containers that have integral bottoms or bottom walls are well known. However, such containers can be problematic, especially elongated and / or narrow diameter containers whose remote portions are difficult to reach and effectively clean. In an effort to alleviate this problem, such containers, for example bottles and cups for feeding babies, have been formed as a container assembly having an open bottom, and a removable bottom lid, to allow easy access and separate and clean perfectly every component. These container assemblies require a tight seal between the bottom REF: 128977 open of the container and the lower cover. The seal has been obtained by employing a sealing structure, such as an annular ring seal, which is separate and removable from the other components of the assembly. However, the use of a separate sealing structure makes the container assembly more complicated to assemble and, thus, to use. If it is not removed and cleaned, there may be the possibility that undesirable material, for example liquid, food, and the like, accumulates or forms between the separate sealing structure and its underlying surface. It is desired to have a sealing system for a container assembly with a removable bottom lid that overcomes the aforementioned drawbacks.

BRIEF DESCRIPTION OF THE INVENTION An object of the present invention is to provide a hermetic sealing system for a container assembly having a container with a removable bottom lid. Yet another object of the present invention is to provide such a sealing system in which the sealant is attached to the lower lid of the container assembly. Still another object of the present invention is to provide a container assembly in which the sealant in the bottom cap provides the seal between the bottom cover and the container. Yet another objective of the present invention is to provide an alternative sealant that is secured to the container to provide a seal between the bottom cover and the container. Yet another objective of the present invention is to provide a container assembly in which the lower lid has a sealing material bonded thereto to provide a tight seal between the lower lid and the open bottom of the container and, simultaneously provide a holding surface for the container. through or slightly beyond the outer surface of the lower lid to make contact with a substrate, such as a table. The present invention includes a bottom cap for sealing and sealing the open bottom end of a container. The lower cover includes a bottom wall having a peripheral portion, a side wall extending upwardly from the peripheral portion, and means for securing the bottom cover to the open bottom end of the container. The peripheral portion includes a continuous, preferably annular, peripheral layer of sealing material bonded thereto, which is adapted to hermetically seal the bottom or bottom end of the container, when the bottom cover is secured thereto. The present invention also includes a container assembly comprised of a container having an open lower end, with a sealing surface directed downward, means for securing a lower cover to the open lower end, a lower lid, and a continuous, preferably annular, layer or strip of compressible sealant material attached to the container assembly. The strip is adapted so that when the lower lid is secured to the open lower end, the strip is between the sealing surface and the lower wall, and the sealing surface compresses the strip against the lower wall thereby forming a seal tight between the container and the lower cover. In the container assembly, the strip is preferably attached to the interior surface of the bottom or bottom wall of the bottom cover. Also preferably, the peripheral portion of the lower cover has holes therethrough and the sealing material extends into and slightly through the holes. The sealing material extending into the holes preferably extends below the bottom surface of the bottom wall of each hole, where it may be in the form of an individual protrusion below each hole. Each protrusion preferably has a peripheral edge that underlies and is attached to the bottom surface of the bottom wall. Also, preferably, the peripheral portion has an annular array of holes circumferentially spaced therethrough, and the sealing material of the strip extends through and below the holes, and is in the form of a continuous, preferably annular, layer , which is fused to the lower surface of the peripheral portion. The present invention also includes a method for forming the bottom cap of the present invention. The method includes forming the bottom cap of a first material, and injecting a sealing material over the peripheral portion of the bottom cap so that the sealing material forms an annular layer on the peripheral portion. The injection step is effected at a temperature and under conditions sufficient to fuse the layer of sealing material to the peripheral portion. The forming step preferably includes the formation of an annular series of circumferentially spaced holes through the peripheral portion of the lower wall, and the injection passage preferably includes the flow of the sealing material through and below the holes, so that the sealing material below the holes forms either a series of protuberances or an underlying annular layer, which fuses to the bottom or bottom surface of the bottom wall. Preferably, the underlying layer is formed such that it has outer edges that are underlying the lower wall, adjacent to the holes. In the method, the bottom or bottom cap is preferably made of polypropylene, and the sealing material is preferably a thermoplastic elastomer having a Shore A hardness of about 40 to about 50.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front elevational view of a container assembly of the present invention; Figure 2 is a front elevation view of the container body of the container assembly of the Figure 1; Figure 3 is a vertical sectional view, with divided portions, of the open lower end of the container body of Figure 2; Figure 4 is a vertical sectional view, with divided portions, of the lower end of the container assembly of Figure 1; Figure 5 is an enlarged vertical sectional view, with divided portions, of the lower left portion of the container assembly of Figure 4; Figure 6 is an enlarged, vertical sectional view with divided portions of an alternative embodiment of the container assembly of the present invention; Figure 7 is a top plan view of the lower lid of Figure 6; Figure 8 is an enlarged, vertical sectional view of the preferred bottom or bottom lid of Figure 6, as seen along line 8-8 of Figure 7; Figure 8A is a vertical sectional view, enlarged, with divided portions, of a portion of a lower lid having a protrusion on the bottom thereof; Figure 9 is a bottom plan view, with divided portions, of the lower lid of Figure 7; Figure 9A is a bottom plan view, with divided portions, of a bottom or bottom cap having protuberances on the bottom thereof; Figure 10 is a vertical sectional view through the alternative embodiment of the lower lid of the present invention, shown without a sealing material; Figure 11 is an enlarged sectional view of a lower right portion of the lower lid of Figure 10; Figure 12 is a top plan view with divided portions of the lower lid of Figure 10; Figure 13 is a bottom plan view, with divided portions, of the lower lid of Figure 10; Y Figure 14 is a flow diagram showing the method steps of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES With reference to the drawings and, in particular to Figure 1, a preferred container assembly of the present invention is shown, generally represented by the reference number 10. The container assembly 10 includes a container 20, and a lower cover or bottom 50, removably secured to the container. As shown in Figures 2 and 3, the container 20 has a body 22 having an open lower end or portion 24. The lower end 24 preferably has a cylindrical neck 26, a sealing surface 28 directed downward, and the structure , such as, for example, an external thread 30, for securing the lower cover 50 to the body 22 of the container, and, thus, to the container 20. The sealing surface 28 has a edge 32 defining a lower opening 34. Preferably, the lower opening 34 is a wide-mouth opening. Figures 4 and 5 show the lower lid 50 which closes and hermetically seals the lower end 24 of the container body 22. The lower lid 50, also shown in Figure 8, is a preferred embodiment of the lower lid of the present invention. The inner lid 50 has a lower wall 52 with an inner surface 53 and a peripheral portion 54, and an upwardly extending side wall, shown here as the cylindrical peripheral wall 56. The wall 56 has the structure, such as example, an internal thread 58 which is adapted to be threadedly engaged to the threads 30 to secure the lower cover 50 to the neck 26 of the container body 22. The lower lid 50 also has a peripheral, continuous, annular strip or layer of sealing material 60 attached to the peripheral portion 54 of the lower wall 52. As more clearly seen in Figure 5, when the lower lid 50 is threadedly secured to the lower end 24 of the container body 22, the sealing surface 25 of the neck 26 engages and compresses the strip 60 whereby a tight seal is formed between the sealing surface 28 and the bottom wall 52. Preferably, the peripheral portion 54 of the bottom wall 52 has a series of the apertures or holes 70 circumferentially spaced therethrough, and the strip 60 extends into and through and preferably projects below the holes 70 in the bottom surface 53 of the bottom wall 52. The sealing material of the strip 60 of sealing material in each hole 70 is referred to as a post 61. As shown in Figures 8A and 9A, the portion of the post 61 projecting below the holes 70 may be in the form of an individual bulge 63 below each hole. The protrusion 63 preferably has a peripheral edge 64 that extends below and preferably is attached to the lower surface 53 adjacent each hole 70. The edges 64 of the protuberances 63 are advantageous because they form at least one mechanical interlocking, and preferably joined, between the underlying edges and the exterior of the bottom surface 53 of the bottom wall 52. This helps to prevent or prevent the strip 60 from being removed from the bottom wall 52.

Alternatively, the post 61 of the strip 60 extending through the hole 70 communicates with a continuous, preferably annular, underlying strip or layer of the sealing material 62 below and preferably attached to the lower surface 53 of the bottom wall 52 The underlying layer 62, like each protrusion 63, preferably also has side edges 64 that run underneath and preferably are attached to the bottom surface 53 of the bottom wall 52 adjacent the holes 70. As shown in Figure 9, a plurality of protuberances (not shown) in series can form a continuous or discontinuous layer or, more preferably, the underlying layer 62 of the sealing material. The individual, discontinuous protrusions, continuously, or the underlying layer 62 of the sealing material (shown in Figure 9), are advantageous because they form an anti-slip, anti-scratch holding surface on a support surface such as an upper part of a table. (not shown). Also, Figure 9 shows that the continuous underlying layer 62 has side edges 64 that run under and are preferably attached to the interior surface 53 of the bottom wall 52. Figures 4, 5 and 8 show that the strip 60 is preferably positioned such that a portion thereof fills and is joined to the junction of or a portion of the junction of the lower wall 52 and the side wall 56 of the lower cover 50. The strip 60 is preferably attached to a portion of the side wall 56. The connection of the lower wall 52 and the side wall 56 can be of any suitable shape. For example, it may have a step in it as shown in the lower cover 50, preferred, of Figures 5 and 8, it may be angular (not shown), or it may be curved, as shown in the alternative lower cover 50. 'in Figures 6 and 10. Figure 6 shows a lower portion of an alternative embodiment of a container assembly 10' of the lid of the present invention, generally represented by the reference numeral 10 '. The structure or elements that are similar to or equal to those shown in Figures 1 through 5 and 7 through 9 are identified by the same reference number with a prime or apostrophe. More particularly, Figure 6 shows the alternative bottom cap 50 '(also shown in Figure 10), secured to, sealing and hermetically sealing the open bottom end 24' of the body 22 'of the container. Figures 6 and 10 show that the junction of the lower wall 52 'and the side wall 56' is curved, and the portion of the annular layer or strip 60 'above the lower wall 52' is wider and thinner than the layer 60 of the lower cover 50 (Figures 4, 5 and 8). Figures 6 and 10 also show that the sealing surface 28 ', of the neck 26' of the lower end 24 'is wider than the sealing surface 28 of Figure 5. The sealing surface 28' compresses a wider extension of the sealing surface 28 '. layer 60 'that the sealing surface 28 which compresses the layer 60 in Figure 5. Figure 7 shows that the layer 60, attached to the upper surface of the peripheral portion 54 on the lower wall 52, is annular and continuous and has lateral edges that extend above and are joined to the upper surface of the peripheral portion. Figure 7 also shows the annular series of circumferentially spaced holes 70 and posts 61 therein. Figure 8 shows a preferred vertical cross section of the layer 60, the post 61 and the layer 62 of the lower lid 50, when the layer 60 is not compressed by a sealing surface of an open lower end of the container. Figure 10 shows the alternative bottom cover 50 'of the present invention which was discussed above in connection with Figure 6. Figure 10 shows that the central portion of the bottom wall 52' of the bottom cover 50 'is preferably concave when observe from the bottom, most or all of the peripheral portion 54 ', especially its outer peripheral portion, is substantially flat and substantially horizontal, and the peripheral portion 54' communicates with the side wall 56 'through a joint that is concavely arched when viewed from the inner part of the lower lid 50 '. The concave shape of the central portion of the bottom wall 52 'adds resistance to the bottom wall. The substantially flat and horizontal arrangement of the peripheral portion 54 'and the shape of the joint and the proximity of the side wall 56' to the peripheral portion 54 ', helps to place and form the continuous, annular peripheral layer 60' of the material. sealant on the peripheral portion 54 '. Figure 11 shows that each hole 70 'preferably has an annular recess 72' therethrough to facilitate the formation of the hole. The recess 72 'also facilitates the flow of the sealing material from the hole 72' to the underlying portions of the lower surface 53 'adjacent the holes 70' in the bottom wall 52 '. Figure 12 shows the annular series of holes 70 'formed around the peripheral portion 54 of the lower wall 52', and Figure 13 shows a recess 72 'in the lower surface 53' around each hole 70 'in the bottom wall 52 '.

According to the present invention, the hermetic seal made between the lower end 24 and the lower covers 50, 50 'can be effected in any suitable way or in any suitable place, with the proviso that the sealing material is preferably attached to the lower lid 24, or alternatively to the bottom of the neck 26. When the lower lid 50, 50 'is secured to the lower end 24, the sealing material will be placed or located between and compressed to form a hermetic seal between a sealing surface 28, 28 'of the lower end 24, 24', respectively, and an opposing sealing surface, for example the lower wall 52, 52 'of the lower cover 50, 50', respectively. In this way, a suitably shaped sealing material can be attached to a portion of either the lower end 24 or the lower lid 50, 50 '. Although not preferred, a strip, layer or other suitable shape, for example an annular ring of the sealing material, can be attached to the sealing surface 28 of the lower end 24. The container 20, 20 'and the lower cover 50, 50 They can be made of any rigid or substantially rigid, suitable material, which retains its shape and can be sterilized, washed or cleaned, especially at elevated temperatures. Although glass or metal can be used, plastics, polyesters, polyamides, polyolefins, polyamides, polycarbonates, polyacrylates and polyurethanes, and the like, are rigid or substantially rigid. When the container 20, 20 'is for the formation of a container assembly for containing milk or other liquid product for infants, the preferred material for forming the body 22, 22' of the container, is a polyolefin. The polyolefin is, for example, an ethylene or propylene polymer such as polypropylene, or, more preferably, a polycarbonate. The lower lid 50, 50 'is preferably made of a polyolefin, for example, a polymer or copolymer of propylene or ethylene, or a combination thereof. Although ethylene polymers, such as high density polyethylene, may be employed, the preferred material for the bottom cap 50, 50 'is polypropylene. Sealing materials for the layer 60, 60 'and the like, suitable for use in the present invention, are compressible during use such that when the lower cover 50 is secured, preferably threaded securely, to open the lower end 24, 24' , the sealing surface will compress the layer 60, 60 'and will form an airtight seal therewith.

The sealant material suitable for use in the present invention is compressible and must be unreachable, preferably directly, to the material of the substrate or structure, for example, to the lower lid 50 or to the body 22 of the container to which the sealing material. Suitable sealing materials include silicones, urethanes and elastomers. Preferred elastomers are thermoplastic elastomers, sometimes referred to as "TPEs". The suitable sealing materials for the layer 60, 60 'include those which preferably have a Shore A hardness of from about 30 to about 60, more preferably from about 40 to about 50, and most preferably about 45. The hardness values described or indicated herein are obtained by the use of a durometer. Sealing materials having a Shore A hardness progressively above about 60 and particularly approaching 100, would be expected to be too hard and inflexible to be compressed to form an airtight seal, and materials having a Shore A hardness progressively below about 30 one might expect them to be progressively too soft and sticky to form airtight, practically operable watertight seals.

According to the present invention, the connection of the sealing material to the surface or structure for example of the lower end 24 or the lower cover 50, it can be carried out in any suitable manner by any suitable means, as long as the attached sealing material is integral or unitary with the surface or structure to which it is attached. "Integral or unitary" means that the sealing material is one with or a unit with the surface or structure, so that dust, food, liquid or other material can not accumulate, be formed or otherwise be constituted or be between the sealing material and the surface or structure. As will be more fully explained below, the preferred bond is obtained by fusing between the sealant material and the surface material or substrate structure. Although less preferred, the bond can be achieved by the use of one or more adherents, mixed with the sealant material and / or employed as one or more layers between the sealant material and the surface or structure. The adherent must be compatible with and must unite integrally or unitarily, the sealant material and the surface or structure a, on or against which the sealant material and / or the adherent is bonded. It is understood that the sealing material and any adherent material must be suitable for the intended application for the container assembly or the lower cover. For example, for a container and lower lid assembly that will be subject to sterilization or washing at elevated temperatures, or cleaned with certain chemicals, the sealing material and the adhesive or adherents must maintain sufficient bond under those conditions. The present invention includes the methods of forming the lower cover 50. The method includes forming the lower cover 50 of a first material by a molding process carried out at an elevated temperature. As shown in Figure 14, preferably the material for forming the lower cover 50 is injected into a shaped mold to form a desired lower cover, with the bottom having the peripheral portion or wall 53, a side wall 56 threaded , erect and, preferably, an annular series of holes 70 circumferentially spaced across the bottom. Once formed, the lower cover 50 can be left in the mold if the injection system and the mold assembly are adapted to inject and form the layer 60, 60 'on the lower wall. Preferably, the lower cover 50 is removed to another mold where its elevated temperature is maintained, or the lower cover is reheated to the desired elevated temperature. In the second mold, the sealing material for forming the layer 60 is injected onto the lower cover 50, preferably on the upper surface of its peripheral portion, to form the layer 60 thereon. The sealant material is injected at a temperature and under conditions sufficient to bind, preferably fuse, the sealant material to the bottom wall. During the injection of the sealing material, the temperature of the lower wall is such that the lower lid 50 is sufficiently rigid to maintain its body and shape, to still be soft enough to join the sealing material. The lower cover 50 with the sealing material on it may need to be left in the mold at an elevated temperature, sufficient to effect the joining. When the lower wall includes the annular series of spaced holes 70, the molds are adapted, and the injection of the sealing material includes the flow of the material through and preferably below the holes, so that the sealing material below the holes it has the desired shape and configuration, and is preferably attached to the bottom surface of the bottom wall. Preferably, the forming process is adapted so that any sealing material below the holes, either in the form of protuberances or protrusions or the preferred annular layer, has outer edges that lie underneath and are attached to the lower surface . Preferably, the first material injected to form the bottom cap 50 is polypropylene and the second material injected to form the sealing layer is a thermoplastic elastomer having a Shore A hardness of from about 40 to about 50. The present invention having thus been described with Particular reference to the preferred forms thereof, it will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the present invention as defined in the appended claims.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (32)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A lower lid for closing and sealing the lower or open bottom end of a container, the lower lid is characterized in that it comprises: a bottom wall having a substantially flat peripheral portion; a side wall extending in an upward direction from the peripheral portion, the side wall having means for securing the lower cover to the lower end of the container; and a continuous layer of sealing material attached to the peripheral portion of the lower wall, the sealing material is adapted to wrap the lower end of the container, forming a seal when the lower cover is secured thereto.

2. The lower lid according to claim 1, characterized in that the sealing material has a Shore A hardness of about 30 to about 60.

3. The lower lid according to claim 1, characterized in that the sealant is a thermoplastic elastomer having a Shore A hardness of about 40 to about 50.

The lower lid according to claim 1, characterized in that the sealant is an elastomer thermoplastic having a Shore A hardness of about 45.

The lower cap according to claim 1, characterized in that the sealant is fused to the peripheral portion.

The lower cover according to claim 1, characterized in that the peripheral portion has holes through it, and where the sealing material extends into the holes.

The lower cover according to claim 6, characterized in that the lower wall has a lower surface, and wherein the sealing material that extends into the openings, extends below the lower surface of the lower wall.

The lower cover according to claim 7, characterized in that the sealing material below the holes is in the form of an individual projection or protrusion below each hole.

9. The lower lid according to claim 8, characterized in that the protrusions have peripheral edges that extend below the lower surface of the lower wall.

The lower lid according to claim 7, characterized in that the sealing material below the holes is in the form of an underlying, continuous peripheral layer of the sealing material.

The lower cover according to claim 10, characterized in that the holes are arranged in an annular series and are circumferentially spaced from one another, and wherein the underlying continuous layer is attached to the lower surface of the peripheral portion.

A container assembly, characterized in that it comprises: a container having an open lower end with a downwardly directed sealing surface, having an internal surface and an external surface, and means for securing a lower lid to the lower end; a lower lid for closing and sealing the lower end, the lower lid has a substantially flat bottom wall and an upright peripheral wall having means for securing the lower lid to the lower end; and a continuous strip of compressible sealant material attached to the container assembly, the strip is between the sealing surface and the bottom wall so that when the bottom lid is secured to the lower end, the sealing surface compresses the strip against the bottom wall , thereby wrapping the sealing surface, the inner surface and the outer surface, forming a seal between the sealing surface of the container and the lower cover.

The container assembly according to claim 12, characterized in that the sealing material has a Shore A hardness of about 30 to about 60.

The container assembly according to claim 12, characterized in that the sealing material is a thermoplastic elastomer having a Shore A hardness of from about 40 to about 50.

The container assembly according to claim 12, characterized in that the sealing material is a thermoplastic elastomer having a Shore A hardness of about 45.

16. The container assembly according to claim 12, characterized in that the strip is attached to the lower wall of the lower cover.

17. The container assembly according to claim 12, characterized in that the strip is attached to the sealing surface of the lower end of the container.

18. The container assembly according to claim 14, characterized in that the thermoplastic elastomer of the strip is fused to the lower wall of the lower cover.

19. The container assembly according to claim 16, characterized in that the lower wall has a lower surface and a radially inner peripheral portion of the peripheral wall, the peripheral portion has an annular series of holes circumferentially spaced therethrough, and the sealant material of the strip extends through the holes, projects below the bottom surface, and has edges running under the bottom surface.

A container assembly, characterized in that it comprises: a container having a cylindrical lower end, threaded, with a sealing surface directed downwards, having an internal surface and an external surface; and a lower cover for closing and sealing a lower end, the lower cover has a substantially flat bottom wall with a peripheral portion, and a cylindrical peripheral wall, raised, threaded to threadably secure the lower cover to the bottom or bottom end of the container, the peripheral portion of the lower lid has an annular layer of elastomeric, compressible sealant material fused thereto, the sealant material having a Shore A hardness of about 30 to about 60, and the layer is adapted to be compressed by and with this wrapping the sealing surface, the inner surface and the outer surface form a seal with the sealing surface when the lower cover is threadedly secured to the lower end of the container.

The container assembly according to claim 20, characterized in that the elastomeric material is a thermoplastic elastomer having a Shore A hardness of about 45.

22. The container assembly according to claim 20, characterized in that the peripheral portion of the bottom wall has an annular array of openings therethrough, and the elastomeric sealing material is a thermoplastic elastomer which extends through said openings, projects below, and extends below the lower wall adjacent to the walls. openings

23. The container assembly according to claim 22, characterized in that the thermoplastic elastomer that is stretched below the bottom wall is fused thereto.

24. A method for forming a bottom or bottom cap, suitable for closing and sealing the lower open end of a container body wall, characterized in that it comprises: the formation of the lower cover of a first material, the lower cover has a bottom or bottom wall with a substantially flat top surface, a peripheral portion, and a side wall extending upwardly from the peripheral portion, the side wall has internal threads to secure the bottom lid to the bottom open end of the wall of the container body, and the injection of a second material on the lower cover, so that the second material forms an annular layer on the upper surface of the peripheral portion of the lower wall, the second material is an elastomeric sealing material having a sufficient Shore A hardness to make it compressible during use, the injection step being carried out at a temperature and under conditions sufficient to fuse said layer of the elastomeric sealing material to the first material of the peripheral portion.

25. The method according to claim 24, characterized in that the forming step includes the formation of an annular array of circumferentially spaced holes through the peripheral portion of the lower wall, and the injection passage includes the flow of the sealing material through and below the holes, so that the sealant material below the holes has outer edges that extend below the bottom wall adjacent to the holes.

26. The method according to claim 25, characterized in that the injection step includes the formation of the sealing material which extends below the lower wall as an annular layer, and fusing the annular layer to the lower wall.

27. The method according to claim 25, characterized in that the first material is comprised of polypropylene, and the sealing material is a thermoplastic elastomer having a Shore A hardness of about 40 to about 50.

28. A lower lid for closing and sealing the open lower end of a container, the lower lid is characterized in that it comprises: a lower wall having an upper surface, a lower surface, and a peripheral portion having holes therethrough; a side wall extending in an upward direction from the peripheral portion, the side wall having means for securing the lower cover to the lower end of the container; and a continuous layer of sealing material attached to the upper surface of the peripheral portion, and extended through the holes below the lower surface, wherein the sealing material attached to the upper surface is adapted to seal the lower end of the container when the bottom cover is secured thereto and the sealing material extended through the holes below the bottom surface is adapted to form a scratch-proof, non-slip surface on the bottom surface.

29. The lower cover according to claim 28, characterized in that the sealing material below the lower surface is in the form of a single protrusion or protrusion below each hole.

30. The lower cover according to claim 29, characterized in that the protuberances have peripheral edges that run below the lower surface of the lower wall.

31. The lower cover according to claim 28, characterized in that the sealing material below the holes is in the form of a continuous, underlying peripheral layer of the sealing material.

32. The lower cover according to claim 31, characterized in that the holes are arranged in an annular series and are circumferentially spaced from each other, and wherein the underlying continuous layer is attached to the lower surface of the peripheral portion.