Patent Grant
7028866
The present invention relates to dispensers for aerosols or other pressurized products, and more particularly to a pressure resistant plastic bottle for dispensing an aerosol or other comparably pressurized product.
The term “aerosol” will be understood herein to encompass both aerosols, literally, and other liquid or flowable products that can be dispensed from pressurized containers in a manner comparable to aerosolized products. Such products include but are not limited to foamed or gel preparations or to liquid products delivered in a non-aerosol stream.
Pressurized containers for dispensing aerosols are well known in the art, and are typically constructed of metal in order to withstand the inherent internal pressure of aerosols. However, it is desirable to provide a plastic container capable of withstanding the internal pressures generated by an aerosol because plastic has many advantages over metal. Some of these advantages include the ease and economy of manufacture, and aesthetic appeal to an end user.
Despite the desirability of using plastic containers, there are some disadvantages to utilizing plastic materials. For example, it is desirable to avoid plastic containers that have abrupt changes in configuration. The areas of such abrupt changes are stress concentration points which are inherently weak. Another disadvantage is that when the container is subject to internal pressure, certain features of a plastic container may deform. Depending on the wall thickness of the container, the internal volume may change between 3 to 5%. As a result of such stress, slight bulging and/or skewing of the container may occur causing the container to become unsightly, and depending on the location of the deformation the container could become unstable and may not rest properly on a table or other flat surface. It is thus necessary to provide a container design or shape which, when made of a plastic material, can most effectively resist the internal pressures generated by an aerosol without rupturing or becoming unduly distorted. Also, if internal volume changes do occur, then it is desirable that they occur uniformly so that such deformation can be accounted for in the design of the container. Thus, if deformation is known to be uniform, then the container can be designed to accommodate such uniform deformation with the result that the container will be less likely to leak its contents and/or rupture.
The present invention is directed toward a pressure resistant plastic bottle for containing and dispensing an aerosol composition. The plastic bottle is comprised of a hollow elongate body having a longitudinal axis and an outer wall. The outer wall defines a central portion, a top portion and an opposite bottom portion with the central portion having a circular cross-sectional configuration taken through a plane perpendicular to the longitudinal axis and having an inwardly projecting concave configuration extending along its longitudinal direction. Preferably, the central portion of the bottle has a hyperboloid configuration. The bottom portion of the elongate body is integral with the central portion and defines an outwardly projecting convexly shaped configuration extending along a direction transverse to said longitudinal axis. Preferably, the convexly shaped configuration comprises a base portion having a spherical end configuration and a side portion having a spherical segment configuration. This design of the central portion and bottom portion of the plastic bottle effectively resists the internal pressures generated by an aerosol to minimize any deformation. Further, any deformation that may occur results in a substantially uniform change which can be accommodated by the top portion of the plastic bottle.
The top portion of the bottle is integral with the central portion and has an outwardly projecting convex configuration extending along its longitudinal direction, and defines a neck having an opening for receiving and dispensing the aerosol composition. A closure covers the opening and is sealingly attached to the neck to contain the aerosol within the plastic bottle. The top portion of the bottle includes a flat section between the central portion and the neck. The flat section has a constant circular cross section extending along its longitudinal direction to define a cylindrical configuration, and advantageously functions to provide line contact (rather than point contact) between adjacent bottles as they are moved side-by-side down a conveyor belt in contact with each other. Bottles with touching curved surfaces, i.e. point contact, tend to slide up or down thus changing the spacing between bottles. In contrast, bottles having straight surfaces where they touch, i.e. line contact, tend not to slide vertically and maintain a desired spacing during manufacture and filling.
As the bottom portion of the plastic bottle is convexly shaped and the central portion of the plastic bottle preferably is a hyperboloid, there is a need for providing the plastic bottle with a support surface so that the plastic bottle may stand upright when stored. In order to accomplish this, the plastic bottle includes a cap assembly which includes a cap member having a planar top support surface and a depending skirt which is releasably mounted to the top portion of the plastic bottle with a snap-fit arrangement.
The closure includes a valve member having an axially extended valve stem which must be either depressed or tilted to release the aerosol contained in the plastic bottle. In order to accomplish this, the cap assembly includes an actuator integral with the cap member and operably associated with the stem to activate the valve member and dispense the aerosol composition.
In the drawings:
Referring now to the drawings, there is illustrated a pressure resistant plastic bottle generally designated by the numeral 1 for containing and dispensing an aerosol composition. The plastic bottle 1 may be composed of any thermoplastic material that may be formed into the desired shape disclosed herein. Examples of such materials include ethylene based polymers, including ethylene/vinyl acetate, ethylene acrylate, ethylene methacrylate, ethylene methyl acrylate, ethylene methyl methacrylate, ethylene vinyl acetate carbon monoxide, and ethylene N-butyl acrylate carbon monoxide, polybutene-1, high and low density polyethylene, polyethylene blends and chemically modified polyethylene, copolymers of ethylene and C1–C6 mono- or di-unsaturated monomers, polyamides, polybutadiene rubber, polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate; thermoplastic polycarbonates, atactic polyalphaolefms, including atactic polypropylene, polyvinylmethylether and others; thermoplastic polyacrylamides, polyacrylonitrile, copolymers of acrylonitrile and other monomers such as butadiene styrene; polymethyl pentene, polyphenylene sulfide, aromatic polyurethanes; styrene-acrylonitrile, acrylonitrile-butadiene-styrene, styrene-butadiene rubbers, acrylontrile-butadiene-styrene elastomers, polyphenylene sulfide, A-B, A-B-A, A-(B-A)n-B, (A-B)n-Y block polymers wherein the A block comprises a polyvinyl aromatic block such as polystyrene, the B block comprises a rubbery midblock which can be polyisoprene, and optionally hydrogenated, such as polybutadiene, Y comprises a multivalent compound, and n is an integer of at least 3, and mixtures of said substances. The preferred thermoplastic material is polyethylene terephthalate (PET). PET is commercially available from numerous sources, and one such source is MNG, Inc. under the trade designation Traytuf®. Preferably, the thermoplastic polymer used to make the plastic bottle 1 is transparent, although opaque and partially opaque polymers would also function adequately.
The plastic bottle 1 may be formed by any conventional molding technique, such as two-stage blow molding. In two-stage blow molding, a pre-form of the plastic is made by injection molding. The pre-form provides the mass of material that eventually is blown into final shape, but it also may include in substantially final form such features as the bottle neck 11 and annular flange 19, described below. The pre-form is reheated, enclosed within the halves of a blow mold, and thereafter expanded in such mold. Under such a process, the plastic bottle 1 may be formed integrally in a one-piece construction which is the preferred construction. Blow molding techniques, as well as other techniques for manufacturing plastic bottle 1 are well known in the art and need not be further described herein.
Referring now to
Each of compartments 4, 5 have a maximum diameter, and the maximum diameter of compartment 4 compared to the maximum diameter of compartment 5, or vice versa, ranges between a ratio of from about 2 to 1 to about 1 to 1. A ratio greater than 1 to 1 is preferred in that a ratio greater than 1 to 1 results in a single contact location between bottles 1 when multiple bottles are clustered on a conveyer belt or are otherwise being processed, moved, or packaged as a group. Other preferred features with respect to such a contact location are discussed, below. Preferably, the maximum diameter of Du upper compartment 4 is slightly greater than the maximum diameter D1 of lower compartment 5 although just the opposite would also be effective. As shown best in
The bottom portion B of bottle 1 is integral with the central portion C and defines an outwardly projecting convexly shaped or dome shaped configuration extending along a direction transverse to the axis 2. The term “convexly shaped” or “convexly shaped configuration” refers to any curved or rounded shape projecting outwardly from the transverse plane defined by line 28. Examples of such shapes include a hemisphere, an ellipsoid, a hyperbola, a parabola, an arcuate shaped configuration, or an arcuate shaped configuration having multiple arcuate sections such as a combination of a spherical segment having one radius and a spherical end having a second different radius. This latter convexly shaped configuration is the preferred configuration for bottom portion B and is illustrated in
Bottom portion B includes a base portion 6 in the shape of a spherical end defined by a convexly shaped surface having radius R1, and a side portion 7 in the shape of a spherical segment and having an outwardly convexly shaped surface defined by the radius R2. The transition between base portion 6 and side portion 7 is defined by a plane extending perpendicular to axis 2 and is represented by line 31. As shown best in
The top portion T of bottle 1 is integral with the central portion C and has an outwardly projecting convex configuration extending along its longitudinal direction, and defines a cylindrical neck 11 having a tubular opening 12 for receiving and dispensing the aerosol composition. A closure 13 covers the opening 12 and is sealingly attached to neck 11 to contain the aerosol within the body of plastic bottle 1. Closure 13 includes a valve member 14 having an axially extending valve stem 15 which must be either depressed or tilted to release the aerosol composition contained within bottle 1. Valve member 14 and valve stem 15 are conventional components typically utilized in aerosol containers, and need not be further described herein as they are well known in the art. In order to affix closure 13 onto bottle 1, neck 11 includes an outwardly extending annular rim 16 adjacent opening 12, and closure 13 includes a depending flange 17 which is inwardly crimped about rim 16 to retain closure 13 on neck 11 of bottle 1.
As shown best in
Top portion T of bottle 1 also includes an annular flange 19 which projects radially outwardly from neck 11 with respect to longitudinal axis 2. Flange 19 has a thickness sufficient to provide the strength and stability necessary to be an attachment point for the cap member 21, described below. Preferably flange 19 is about four times the minimum thickness of outer wall 3 and terminates at an outer edge 20, which is located at a point between a vertical plane parallel to axis 2 and defined by the outer surface of neck 11 and a vertical plane parallel to axis 2 and defined by the outer surface of wall 3 of top portion T. The outer edge 20 of flange 19 is used as one component in a releasable snap fit mounting arrangement for releasably mounting a cap member 21 to the top portion T of bottle 1, as will hereinafter be described.
As best seen in
The use of flange 19 as an attachment point for the cap member 21 presents important advantages over attachment of the cap member to other locations on the bottle 1. Flange 19 effectively forms a part of the least flexible portions of the bottle 1. Furthermore, flange 19 is contiguous with the structures that define the neck 11. Consequently, when the bottle 1 is under elevated internal pressure, such as can be experienced when a filled and sealed bottle is warmed in the sun or in a hot shower or bath, and thus experiences some degree of deformation and expansion, the relationship of the bottle to the cap member 21 and of the cap member to a valve member 14 mounted within the neck 11 remains stable and virtually unchanged. If the bottle 1 distorts, it is by an extension of the lower, thinner portions of the bottle. Use of the flange 19 attachment location thus avoids such problems as disengagement of the cap member 21 from the bottle 1 or a bottle distortion-caused failure of the cap member to properly relate to the valve member 14.
As the bottom portion B of plastic bottle 1 is convexly shaped, and the central portion C of plastic bottle 1 is preferably a hyperboloid, planar support surface 22 provides a mechanism whereby plastic bottle 1 may stand upright when stored. In order to accomplish this, top support surface 22 is formed in a plane perpendicular to longitudinal axis 2. Also, top support surface 21 is circular in shape and has a diameter which is greater than the diameter of opening 12 in neck 11, but less than the diameter of-top portion T. Support surface 22 thus provides sufficient amount of surface area to enable bottle 1 to stand upright during storage without easily tipping over.
Other modifications of the plastic bottle 1 of the present invention will become apparent to those skilled in the art from an examination of the above description and drawings. Therefore, other variations of plastic bottle 1 may be made which fall within the scope of the following claims even though such variations were not specifically discussed and/or described above. In particular, various types of cap members and closures may be utilized in combination with bottle 1, whether the valve stem 15 is actuated by being tilted or by being depressed or in other ways. Thus, plastic bottle 1 may be suitable for any aerosol product such as insecticides, insect repellents, hairsprays, air fresheners, cleaning preparations, and shave preparations including foams and gels, and the like.
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