PLASTIC AEROSOL CONTAINER, PREFORM AND METHOD

Abstract

A plastic aerosol container (10), an associated preform (10a) and a method of manufacturing the preform (10a) and container (10) is described. The container (10) comprises an adapter (20) that defines an opening (11) of the container (10), the opening (11) being arranged to receive and be sealed by an aerosol valve cap (3). The container (10) also comprises a body 40 that defines an internal volume of the aerosol container (10). The container (10) is blow-moulded from a preform (10a) ideally having a corresponding adapter (20a) and body (40a) which are secured to one another, with an expansion region (45a, 46a) of the body (40a) of the preform (10a) being arranged to be expanded to form the internal volume of the aerosol container (10).

Claims

1. A preform arranged to be blow-moulded into an aerosol container, the preform comprising: an adapter and a body, each having complementary interfaces via which the adapter and body are secured to one another; the adapter defining an opening of the preform, the opening being arranged to receive and be sealed by an aerosol valve cap; and the body comprising an expansion region arranged to be expanded via blow-moulding to form an internal volume of the aerosol container.

2. The preform of claim 1, wherein the adapter and the body are each formed from an integral piece of plastics material, ideally polyethylene terephthalate (PET), wherein the adapter and/or the body are injection-moulded.

3. (canceled)

4. The preform of claim 1, wherein the expansion region of the body is spaced from the interface of the body.

5. The preform of claim 1, wherein the opening is spaced from the interface of the adapter.

6. The preform of claim 1, wherein the complementary interfaces of the body and the adapter comprise joining surfaces that are joined and sealed together along a continuous loop, wherein the complementary interfaces are sealed together via welding, ideally ultrasonic welding.

7. (canceled)

8. The preform of claim 1, wherein the adapter and the body each comprise a flange that extends in an outward direction away from an exterior surface of the respective adapter and body, each flange supporting the interface of the respective adapter and body, wherein the interfaces are supported on respective facing surfaces of the flanges and respective reverse surfaces of the flanges are arranged to transmit a clamping force so as to drive the facing surfaces together.

9. (canceled)

10. The preform of claim 1, wherein the adapter comprises an internal bore that narrows towards the opening, wherein the adapter comprises a radially-inwardly projecting lip around which an aerosol valve cap can be crimp-fitted.

11. (canceled)

12. An adapter and/or body for use in constructing the preform of claim 1.

13. The adapter and/or body of claim 12, comprising at its respective interface at least one energy director shaped to melt upon application of welding energy to facilitate welding of one of the adapter and body to the other.

14. The adapter and/or body of claim 13, formed from an integral piece of plastics material, said energy director being also formed from said integral piece of plastics material and shaped to be more predisposed towards melting upon application of welding energy than an underlying portion of said material.

15. The adapter and/or body of claim 13, wherein the at least one energy director is positioned and arranged so that, when melted upon application of welding energy, it forms a continuous molten loop for joining and sealing together the complementary interfaces of the adapter and/or body.

16. An aerosol container produced from the preform, adapter and/or body of claim 1.

17. An aerosol container produced from a preform constructed from a plastics material, the container comprising: an adapter defining an opening of the container, the opening being arranged to receive and be sealed by an aerosol valve cap; and a body defining an internal volume of the aerosol container; wherein the internal volume defined by the body is substantially derived from an expansion region of the preform expanded by blow-moulding the preform; and the adapter of the aerosol container is substantially derived from a region of the preform unexpanded by said blow-moulding.

18. The aerosol container of claim 16, further comprising a body substantially derived from a blow-moulded expansion region of the preform, wherein the body defines a free-standing base of the container, wherein the free-standing base comprises a rim on which the container is supported.

19. (canceled)

20. The aerosol container of claim 18, wherein an underside of the base defines a first depression, wherein the underside of the base further defines a strengthening formation that interrupts the contour of the first depression, and wherein the strengthening formation comprises a second depression.

21. (canceled)

22. (canceled)

23. The aerosol container of claim 20, wherein the first depression follows the contour of a first oblate spheroid centred on a longitudinal axis of the container, the first depression transitioning into the rim at an axially-lowermost, radially-outer position; and the strengthening formation follows the contour of a second oblate spheroid centred on the longitudinal axis of the container, the second oblate spheroid being smaller than the first oblate spheroid that defines the first depression, the first depression transitioning into the strengthening formation at an axially-upper, radially-inner position of the base.

24. An aerosol assembly, comprising the aerosol container of claim 16 and an aerosol valve.

25. A method of manufacturing comprising: (a) providing an adapter and a body each having complementary interfaces; and (b) securing the complementary interfaces of the adapter and body to one another to produce a preform suitable for blow-moulding into an aerosol container.

26. The method of claim 25, wherein step (a) comprises injection moulding the adapter and body, wherein step (b) comprises welding the complementary interfaces of the adapter and the body together, ideally via ultrasonic welding, and wherein step (b) comprises pressing the complementary interfaces of the adapter and the body together.

27. (canceled)

28. (canceled)

29. The method of claim 25, further comprising: (c) producing an aerosol container by: (i) heating an expansion region of the body, the expansion region being spaced from the interface of the body; and (ii) expanding the expansion region of the body via stretch blow-moulding to form an internal volume of an aerosol container.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] FIG. 1 is a sectional view of an aerosol assembly comprising an aerosol container according to an embodiment of the present invention;

[0063] FIG. 2 is a perspective overhead view of the assembly of FIG. 1;

[0064] FIG. 3 is an underneath perspective view of the assembly of FIG. 1;

[0065] FIG. 4 is a sectional view of the aerosol container of FIG. 1, the container being produced from a preform, the preform comprising an injection-moulded adapter welded to a body, the body being biaxially stretch blow-moulded;

[0066] FIG. 4a is a schematic enlarged partial view of regionaof the container of FIG. 4;

[0067] FIG. 5 is a perspective overhead view of the container of FIG. 4;

[0068] FIG. 6 is an underneath perspective view of the container of FIG. 4;

[0069] FIG. 7 is a sectional view of the preform use to produce the aerosol container of FIG. 4.

[0070] FIG. 8 is a side view of the preform of FIG. 7;

[0071] FIG. 9 is a perspective side view of the preform of FIG. 7;

[0072] FIG. 10 is an exploded sectional view of the preform of FIG. 7;

[0073] FIG. 10a is a schematic enlarged partial view of regionbof the preform of FIG. 10;

[0074] FIG. 11 is an exploded side view of the preform of FIG. 7; and

[0075] FIGS. 12 and 13 are exploded perspective views of the preform of FIG. 7;

SPECIFIC DESCRIPTION

[0076] FIG. 1 is a sectional view of an aerosol assembly 1 comprising an aerosol container 10 according to an embodiment of the present invention. The sectional view of FIG. 1 us taken substantially along a plane parallel to a longitudinal axis X of the container 10. FIGS. 2 and 3 are perspective views of said aerosol assembly 1.

[0077] The aerosol assembly 1 further comprises a conventional aerosol valve assembly 2 which includes an aerosol valve cap 3, a dip tube 4, and an aerosol valve 5. As the aerosol valve assembly 2 is conventional, certain features of it such as a valve stem, spring and inner gasket are omitted in the interests of brevity. The aerosol assembly 1 also comprises a resilient sealing member 6 that is crushed between the valve cap 3 and the container 10 during crimp-fitting of the valve cap 3 to ensure that an opening 11 of the container 10 is hermetically sealed.

[0078] The container 10 is substantially rotationally symmetrical about the longitudinal axis X. Similarly, the aerosol valve cap 3 is also rotationally symmetrical thereby simplifying fitting of the valve cap 3 to the container 10.

[0079] FIG. 4 is a corresponding sectional view of the aerosol container 10 of FIG. 1 shown in isolationi.e. without the aerosol valve assembly 2. FIGS. 5 and 6 are perspective views of said aerosol container 10 of FIG. 4.

[0080] The container 10 is effectively made of two parts; an adapter 20 and a body 40. As will be described in greater detail below, the container 10 is produced from a preform 10a, a sectional view of which is shown in FIG. 7. The preform 10a has an adapter 20a and a body 40a from which the container adapter 20 and body 40 are derived. These are secured and sealed to one another before the preform 10a is used to produce the container 10. Individually, the adapter 20a and body 40a of the preform 10a are each formed from an integral piece of PET that is produced via injection-moulding.

[0081] Referring back to FIG. 4, the adapter 20 defines the opening 11 of the container 10. Specifically, the adapter 20 comprises a lip 21 broadly shaped like a torus and centred on the longitudinal axis X of the container 10. Moreover, at an axially-upper end of the adapter 20, the lip 21 forms a crest of a dome-shaped mouth 22 of the adapter 20.

[0082] These structures can be seen more clearly in FIG. 4a which is a schematic enlarged partial view of regionaof the container 10 of FIG. 4; i.e. an enlarged view of the lip 21. Here it can be seen that the lip 21 and axially-upper end of the mouth 22 extend radially-inwards to define an undercut. This is so that when the aerosol valve cap 3 is crimp-fitted around the lip 21 a lower portion of the valve cap 3 enlarged by the crimping will not be able to fit through the opening; the undercut effectively restrains the valve cap 3 from sliding out from the opening 11 under action of an internal pressure within the aerosol assembly 1.

[0083] The dimensions shown in FIGS. 4 and 4a are replicated here for ease of reference and clarity:

TABLE-US-00001 Description Value Diameter of the opening defined by the lip (25,4) 25.4 mm Radius of curvature of the torus-shaped lip (R1,45) 1.45 mm Radius of curvature of the lower enlarged portion of the 1.5 mm valve cap that is restrained by the lip (R1,5) Difference in radial width between the narrowest part of the 1.15 mm opening as defined by the lip, and the relatively wider widest part of the lower enlarged portion of the valve cap that is restrained by the lip Axial height from the widest part of the lower enlarged 4 mm portion of the valve cap to brim of the container (i.e. the top of the lip)

[0084] Referring back to FIGS. 4, 5 and 6, the dome-shaped mouth 22 is interrupted at an axially-lower end of the adapter 20 by a circumferential flange 23. The circumferential flange 23 generally protrudes from an axially-lower end of the mouth 22 in a radially-outward direction away from the exterior surface of the mouth 22 extending substantially parallel to a plane orthogonal to the longitudinal axis X. The circumferential flange 23 of the adapter 20 is secured along its entire circumference to a complementary flange in the form of a collar 43 of the body 40, thereby sealing and securing the adapter 20 to the body 40.

[0085] The collar 43 is located at an axially-upper end of the body 40. Moreover, it generally protrudes from an axially-upper end of a generally cylindrical neck 44 of the body in a radially-outward direction away from the exterior surface of the neck 44. Similar to the circumferential flange 23, the collar 43 also extends substantially parallel to a plane orthogonal to the longitudinal axis X.

[0086] At an axially-lower end of the neck 44, the neck 44 surmounts and smoothly transitions into a dome-shaped shoulder 45 which, in turn, connects via a first transition zone to a substantially cylindrical side-wall 46 which substantially encircles and is centred on the longitudinal axis X. The circumference of the dome-shaped shoulder 45 at the first transition zone is slightly greater than that of the cylindrical side-wall 46, and so the first transition zone is broadly frustum-shaped tapering radially-inwards from the axially-lower end of the shoulder 45 to the axially-upper end of the side-wall 46. The major circumference of the container is approximately 150 mm.

[0087] At the axially-lower end of the side-wall 46, it connects via a second transition zone to a trunk region 47 of the body 40. The trunk region 47 assumes an inverted and truncated dome shape, generally tapering radially-inwards towards an axially-lowermost end of the body 40. The circumference of the trunk region 47 at the second transition zone is slightly greater than that of the cylindrical side-wall 46, and so the second transition zone is also broadly frustum-shaped tapering radially-outwards from the axially-lower end of the side-wall 46 to the axially-upper end of the trunk region 47. At its axially-lowermost end, the body 40 curves in on itself to define a rim 48 which provides continuous contact region on which the container 10 is stably supported. The rim 48 forms part of a pressure-resistant freestanding base 50 of the body 40 and so the container 10 in general.

[0088] Radially-inward of the rim 48, when viewed from an exterior of the container 10, the underside of the base 50 is generally concave. Specifically, the underside of the base 50 defines a first depression 51 that follows the contour of a first oblate spheroid centred on a longitudinal axis X of the container 10. The first depression 51 and rim merge together at an axially-lower, radially-outer position of the base 50. The underside of the base 50 also defines a strengthening formation in the form of a second depression 52. The second depression also follows the contour of a second oblate spheroid centred on the longitudinal axis X of the container 10. However, the second oblate spheroid is smaller than the first oblate spheroid that defines the first depression 51, and extends to an axially-higher position than the first oblate spheroid. Thus, the second depression 52 interrupts the contour of the first depression 51 at an axially-upper, radially-inner position of the first depression 51, the transition between the first and second depressions being defined by frustoconical transition portion 53.

[0089] The features of the adapter 20, such as the lip 21, mouth 22 and flange 23 are integral with one another in that they are constructed from an integral piece of PET. Similarly, the feature of the body 40, such as the collar 43, neck 44, shoulder 45, side-wall 46, trunk region 47 and base 50 are also integral with one another.

[0090] As mentioned, the container 10 is produced from the preform 10a. Moreover, and referring back to FIG. 7, the container 10 is blow-moulded from the preform 10a. Specifically, comparing FIG. 7 with FIG. 4, it is an expansion region of the body 40a of the preform 10a that is biaxially stretch blow-moulded to form expanded parts of the body 40 of the container 10. The expanded parts of the body 40 can be readily discerned from FIG. 4 as their walls are significantly thinner than those of the unexpanded parts of the body 40. For the avoidance of doubt, the expanded parts of the body 40 include the base 50, trunk region 47, side-wall 46 and most of the shoulder 45. The unexpanded parts of the body 40 include the axially upper-end of the shoulder 45, the neck 44 and the collar 43.

[0091] In contrast, the adapter 20a of the preform 10a is not modified by the conversion from the preform 10a to container 10; i.e. it is not deformed by the act of blow-moulding. Accordingly, and referring to FIGS. 7 to 9, the adapter 20a of the preform 10a has the same principle features of the adapter 20 of the container 10. Similarly, the unexpanded parts of the body 40 of the container 10namely, the collar 43 and the neck 44 substantially match those of the preform 10a. Thus, these features in common are denoted by like reference numerals.

[0092] Unlike the body 20 of the container 10, the body 20a of the preform 10a comprises a generally frustoconical throat portion 45a and a generally bullet-shaped tail portion 46a. These together define the main expansion region of the body 20a of the preform 10a.

[0093] The tail portion 46a comprises a shaft 47a that joins on to the throat portion 45a at its axially-upper end. The shaft 47a is terminated at the axially-lower end of the preform 10a by a spheroidal tip 48a which defines a closed end of the preform 10a. Whilst the shaft is broadly cylindrical in shape, it does slightly tapered radially-inwards in the direction of the tip 48a. This, in combination with a substantially constant wall thickness provides the body 40a with a draft that allows it to be easily withdrawn from an injection mould. Moreover, the body 40a has an internal blind-bore that widens in the direction of the aperture at the axially-upper end of the body 40a, as delimited by the collar 43.

[0094] Similarly, it should be noted that the internal bore of the adapter 20a widens in one directioni.e. from the lip 21 at the axially-upper end of the adapter 20a to the axially-lower end of the adapter 20a adjacent the flange 23. However, whilst the internal bore of the body 40a is a blind-bore that is closed at the tip 48a, the internal bore of the adapter 20a is a through-bore.

[0095] Accordingly, the preform 10a formed by the joined adapter 20a and body 40a has an internal bore that is narrower at the ends of the preform 10a (i.e. the tip 48a and lip 21) than in the middle (i.e. at the flange 23 and collar 43). Such a preform cannot be produced in one piece via conventional injection moulding techniques.

[0096] FIG. 10 is an exploded sectional view of the preform of FIG. 7, showing the adapter 20a and the body 40a as individual parts. As will now be described in greater detail, the adapter 20a and body 40a are secured and sealed together to create the preform 10a. This is achieved via the complementary interfaces of the adapter 20a and the body 40a, which are presently embodied by the circumferential flange 23 of the adapter 20a and the collar 43 of the body 40a.

[0097] FIG. 10a is a schematic enlarged partial view of regionbof the preform of FIG. 10 which shows the structure of the circumferential flange 23 and the collar 43 in more detail. In general, the circumferential flange 23 of the adapter 20a defines an annular groove 231 within which the collar 43 of the body 40a can be received when the adapter 20a and body 40a are joined together. Thus, the flange 23 and collar 43 effectively define mating structures that mate the adapter 20a and body 40a together, with the collar 43 locating within the circumferential flange 23.

[0098] In more detail, the collar 43 extends in a radially-outward direction away from an exterior surface of the underlying neck 44 with which it is integrally-formed. Furthermore, it is offset radially-outwards from the underlying neck 44 of the body 40a so that a radially-inner part of the axially-upper end of the neck 44 defines an axially-upwardly facing seat 440. The collar 43 merges to the corresponding radially-outer part of the axially-upper end of the neck 44. The collar 43 also extends in axially-upward direction. The collar 43 is broadly of the shape of a rectangular toroid, but with its axially-upper edges 435, 436 being chamfered, and its axially-lower, radially-inner edge merging smoothly with the neck 44. The collar 43 thereby defines an axially-upwardly-facing joining surface 430, and an axially-downwardly-facing clamping surface 431.

[0099] In complement, the circumferential flange 23 of the adapter 20a comprises an annular portion 230 which extends in a radially-outward direction away from an exterior surface of the mouth 22 with which the flange 23 is integrally-formed. The annular portion 230 is subtended at its radially-outer end by a first circumferential skirt 235 which extends axially downwards, bounding one side of the annular groove 231. The annular portion 230 is subtended at its radially-inner end by a second circumferential skirt 236 which also extends axially downwards, and defines the other side of the annular groove 231. The annular portion 230 also comprises an axially-downwardly-facing joining surface 232, and an axially-upwardly-facing clamping surface 234.

[0100] The annular groove 231 defined by the circumferential flange 23 has a radial width, and an axial height that accommodates the collar 43 such that when the adapter 20a and body 40a are sealed to one another, the respective joining surfaces 232, 430 contact one another and the skirts 235, 236 locate either side of the collar 43, with the second circumferential skirt 236 substantially joining the seat 440 of the neck 44. The radial width and positioning of the mated seat 440 and second circumferential skirt 236 match one another. Accordingly, the diameter of the internal bore across the interface of the adapter 20a and the body 40a is substantially constant.

[0101] The chamfered edges 435, 436 of the collar 43 mean that annular gaps each of approximately triangular section are defined between the chamfered edges 435, 436 of the collar 43 and the non-chamfered corners of the annular groove 231.

[0102] Integrally-formed with, and projecting from the joining surface 232 of the annular portion 230 are a concentric pair of energy directors 450, 451 each of which are broadly of the shape of a triangular toroid. The radial distance a1 between each energy director 450, 451 is approximately 1.8 mm, and the axial height a2 of each energy director 450, 451 is approximately 0.4 mm. In alternatives, the radial distance a1 is typically within the range 0.5 mm to 3 mm, and the axial height a2 is typically within the range 0.2 mm to 0.7 mm. In the sectional view shown in FIG. 10a, two axially-downwardly-facing faces of each energy director 450, 451 are at right-angles to one another such that each energy director terminates at a sharp circular apex.

[0103] As mentioned previously, the adapter 20a and body 40a of the preform 10a are each made from an integral piece of PET produced via injection-moulding. In particular, they are produced as individual parts which are then welded together to create the preform 10a as will be described with reference to FIG. 11, which is an exploded side view of the preform of FIG. 7.

[0104] The adapter 20a and the body 40a are positioned so that their respective central longitudinal axes are aligned along the common longitudinal axis X. The adapter 20a and the body 40a are then moved towards one another along said axis X until their complementary interfaces partially mate, with the apices of the energy directors 450, 451 being pressed against the axially-upwardly-facing joining surface 430 of the collar 43. A clamping force is applied via the clamping surfaces 234, 431 of the flange 23 and collar 43 and a welding energy is applied locally to the region of the adapter 20a and body 40a adjacent to the joining surfaces 430, 232. Specifically, a sonotrode is applied to the clamping surface 234 of the flange 23 so that high-frequency ultrasonic vibrations are passed through to the energy directors 450, 451, the apices of which vibrate relative to the adjoining joining surface 430 of the collar 43. The sharp contact edge of the apices of the energy directors 450, 451 concentrates the welding energy so that the energy directors 450, 451 melt before any other underlying material of the flange 23 and collar 43. The toroidal shape of the concentric energy directors 450, 451 results in two molten loops being formed. These molten loops coalesce together as the energy directors 450, 451 continue to melt and the adapter 20a and body 40a are pressed closer together. Furthermore, as the gap between the facing joining surfaces 232, 430 narrows, the molten material is squeezed to the radial extremities of the joining surfaces 232, 430. However, flow of molten material is substantially confined to the joining surfaces 232, 430 by the annular gaps between the chamfered edges 435, 436 of the collar 43 and the non-chamfered corners of the annular groove 231. Thus, these annular gaps effectively define weld sinks that form the boundaries of the region of the adapter 20a and body 40a that are to be welded together. A weld zone can thereby be accurately established.

[0105] When substantially all the material forming the energy directors 450, 451 has melted and the complementary interfaces are in a fully mated position, the welding energy is removed and the weld allowed to cool. The preform 10a is thereby formed, and ready for stretch blow-moulding to form the aerosol container 10.

[0106] Specifically, biaxial stretch blow-moulding of the preform 10a is carried out by heating the preform 10a at the expansion region of the tail portion 46a, applying a push-rod via the internal bore to stretch the tail portion 46a in the axial direction, and then blowing air into the preform 10a to expand it in a radially-outward direction to take the shape of a mould. The resulting biaxially-stretched container 10 is highly resistant to internal pressure.

[0107] The axial spacing of the interface and, moreover, the opening from the expansion region ensures that the opening is not deformed by the stretch blow-moulding operation. Therefore, the reliability with which the aerosol valve cap is subsequently fitted to the opening to produce an aerosol assembly is increased.

[0108] Further features and advantages will be apparent to a person skilled in the art considering the drawings. Furthermore, modifications and variants to the present embodiment will be apparent to a person skilled in the art.