GB2430930A

GB2430930A - Closure with a projection having an angled surface

Info

Publication number: GB2430930A
Application number: GB0616902A
Authority: GB
Inventors: Keith Douglas
Original assignee: Ecocap Ltd
Current assignee: Ecocap Ltd
Priority date: 2005-09-12
Filing date: 2006-08-25
Publication date: 2007-04-11
Also published as: DK1931573T3; GB0518593D0; ES2403830T3; CN101370714B; GB2429971A; US20100065569A1; GB0616902D0; CN101370714A

Abstract

A closure 2 for closing an opening of a container 22, The closure comprising attachment means for attaching, in use, the closure to the container, a sealing surface 12 inclined to a plane perpendicular to a central axis of the closure, and located such that when the closure is attached to the container by the attachment means the sealing surface is engageable with the container. The angled sealing surface 12 may be provided on a projection 10 which extends from a top 4 of the closure 2. The angled surface 12 may also have an arcuate profile. In another embodiment a closure is formed from a thermoplastic polymeric material comprising polylactic acid or a derivative thereof, and wherein the thermoplastic polymeric material is amorphous or at least partially amorphous. In a further embodiment (see figures 7 and 8) a closure may be provided with a thread or groove for engaging with a corresponding portion of a container, wherein the closure is deformable on engagement with the container wherein the container can flatten a curved external surface of the closure.

Description

CLOSURE

The present invention relates to a closure for closing an opening of a container. In particular, it relates to a closure device which is screwed onto a drinks container.

It is known to package potable fluids such as water in a container having a detachable closure to seal the container. The container and closure are typically moulded.

A thread or groove is formed on the bottle, around the opening, and a complimentary thread or groove is formed on the inside of the closure. If there are any inaccuracies in the moulding of the thread and groove, then the cap may not form a fluid tight seal over the opening. This may result in a leakage of fluid from the container.

The present invention provides, in a first aspect, a closure for closing an opening of a container, the closure comprising: attachment means for attaching, in use, the closure to the container; a sealing surface inclined to a plane perpendicular to a central axis of the closure, and located such that when the closure is attached to the container by the attachment means the sealing surface is engageable with the container.

The present invention provides, in a second aspect, a closure in combination with a container; the combination comprising: an attachment means for removeably attaching the closure to the container; the container comprising a neck defining an opening; the closure for closing the opening and comprising a sealing surface; the sealing surface inclined to a plane perpendicular to a central axis of the closure; the sealing surface located such that when the closure is attached to the container by the attachment means, the neck engages the sealing surface.

This has the advantage that a fluid tight seal is formed between the closure and the container, even if there are inaccuracies in the moulding of the closure or container.

Preferably, the neck of the container comprises a radiussed surface, the radiussed surface engageable with the sealing surface of the closure. Thus, a good seal is provided between the closure and the container.

Preferably, the sealing surface faces radially outwardly from the central axis of the closure. Thus, a good seal is provided between the closure and the container.

Preferably, the closure further comprises a second sealing surface inclined to the central axis of the closure.

Thus, the second sealing surface improves the seal between the closure and the container.

Preferably, the second sealing surface faces radially inwardly towards the central axis of the closure. Thus, the sealing surfaces face in opposite directions to provide a good seal.

Preferably, the neck comprises a radiussed surface for engagement with the second sealing surface. Thus, the surface area of the neck in contact with the sealing surface is increased.

Preferably, the or each sealing surface is annular.

Thus, a uniform sealing surface is provided which can be readily engaged with the container.

Preferably, the attachment means comprises one or more helical threads and grooves. Thus, a secure and releasable engagement means is provided.

Preferably, the or each projection comprises a cavity.

Thus, the projection is readily deformable when urged against the neck of the container, to ensure that a good seal is formed even if there are inaccuracies in the moulding.

Preferably, the neck comprises one or more cavity or cavities. Thus, the neck is readily deformable when urged against the sealing surface of the closure, to ensure that a good seal is formed even if there are inaccuracies in the moulding.

Preferably, the closure comprises a stop to limit movement of the neck relative to the closure. Thus, the projection or neck is not deformed so much that plastic deformation or breakage occurs.

Preferably, the closure is integrally moulded. Thus, the closure can be cheaply manufactured.

The following discussion is relevant to both the first and second aspects.

The closure or at least part of the closure will typically be formed from a polymeric material such as a thermoplastic or thermosetting material. A thermoplastic material is, however, preferred. Advantageously, the thermoplastic polymeric material comprises polylactic acid (PLP) (also known as poly(lactide) or poly(lactic acid)) or a derivative thereof. This material has suitable mechanical, chemical and barrier properties and, furthermore, is an environmentally friendly material.

The skilled person will recognise that many suitable polymers can be used in conjunction with the present invention, either by themselves or as a blend. Some other examples of polymeric materials include PHA (poly hydroxy- alkarioate, which is also a biodegradable polymer), polyethylene (including high density polyethylene (FIDPE)), polypropylene and poly(ethylene terephthalate).

The inventor have found that it is advantageous if the polymeric material (e.g. PLA) is amorphous or at least partially amorphous. This has been found to result in improved mechanical properties. In particular, it has been found that a closure formed from a polymer having a high degree of crystallinity can be difficult to remove from the container, for example a plastic bottle with a screw thread attachment. Moreover, a highly crystalline polymer closure can fracture when it is attached to the container. A highly crystalline polymer may also result in the closure locking up or jamming on the bottle. Having identified this problem the inventor have found that improved mechanical properties can be achieved if the degree of crystallinity (volume) in the polymeric material is preferably less than 50 6, more preferably less than 30 %, still more preferably less than %.

The degree of crystallinity in the polymer material forming the closure may be reduced in a number of ways. For example, if the closure is formed by injection moulding or compression moulding, then desirable results can be achieved by ensuring that the mould cavity is filled relatively quickly, for example in = 1 second, preferably = 0.5 seconds. Moreover, it is preferable that heat is removed from the closure, once moulded, as quickly as possible.

Heat can be conducted away from the moulded closure through the mould parts, for example the metal core and cavity.

Cooling means are preferably provided to cool the metal core and cavity. It is also preferable if the wall section of the moulded closure is = 2 mm, preferably = 1 nun.

The closure is preferably integrally formed from the polymeric material (e.g. PLA).

As to manufacture, the closure may, for example, be injection moulded or compression moulded.

In a further aspect, the present invention provides a closure for closing an opening of a container, wherein at least a part of the closure is formed from a thermoplastic polymeric material comprising polylactic acid (PLA) (also known as poly(lactide)) or a derivative thereof, and wherein the thermoplastic polymeric material is amorphous or at least partially amorphous.

The foregoing discussion in relation to the first and second aspects is also applicable to the further aspect of the present invention.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a cross-sectional view of a closure and container in accordance with the present invention; Figure 2 is a cross-sectional view of a second embodiment of the closure and container; Figure 3a is a cross sectional view of a third embodiment of the closure and container; Figure 3b is a cross sectional view of a fourth embodiment of the closure and container; Figure 4 is a cross sectional view of a fifth embodiment of the closure and container; Figure 5 is a cross sectional view of a sixth embodiment of the closure and container; Figure 6 is a cross sectional view of a seventh embodiment of the closure and container; Figure 7 is a cross sectional view of an eighth embodiment of the closure and container; Figure 8 is a cross sectional view of a ninth embodiment of the closure; Figure 9 is a plan view of the closure; Figure 10 is a plan view of the closure engaged with container; Figure 11 is a cross-section through the closure of Figure 10 along a line A-A; and Figure 12 is a cross-section through the closure of Figure 10 along a line B-B.

Referring to Figure 1 there is shown a container 22 having a neck 20. The remainder of the container 22 is not shown as its body shape may take any suitable form and may, for example, be of square, rectangular or circular cross- section, or another geometrical shape.

The neck 20 defines a circular opening 28 having a central axis and surrounded by a substantially smooth, cylindrical internal surface 30. An internal edge 24 is formed at an end of the internal surface 30 remote from the body of the container 22. An external surface 32 of the neck has an external edge 26 at an end remote from the body of the container 22, the external edge 26 being radially outside the internal edge 24.

The external surface 32 is provided with attachment means with which to engage complementary attachment means provided on a closure. The attachment means may take the form of a helical thread or groove 34. The thread or groove 34 may be a single thread or groove, or alternatively be in the form of a plurality of threads or grooves having different starting points.

The closure 2 is also shown in Figure 1. The closure 1 has a top 4 which is circular in plan view, and merges at a radially outer edge with a depending annular side wall 6.

The side wall 6 is provided, on its inner surface, with attachment means for releasable engagement with the complementary attachment means provided on the neck 20. The attachment means may take the form of one or more helical threads or grooves 8. The side wall 6 defines a central axis, extending longitudinally along an axis of symmetry of the closure. The central axis is marked as line A-A on Figure 1.

The closure 2 is provided with an annular projection 10 extending from the top 4, the projection 10 extending from the same side of the top 4 as the side wall 6. The projection 10 is provided with an angled, or sealing, surface 12, which faces radially outwardly and away from the top 4. The angled surface 12 is preferably angled at 45 degrees to the top 4, and may be angled between 10 and 80 degrees. The angled surface 12 can be considered to be inclined to a plane perpendicular to the central axis of the closure. The angled surface 12 could also be considered to be inclined to the longitudinal axis of the threads or grooves 8 of the closure.

The annular projection 10 is circumferentially spaced apart from the side walls 6. The angled surface 12 is located such that when the closure 2 is attached to the container 22 by the attachment means, the internal edge 24 of the neck 20 abuts against the angled surface 12 in order to close the opening 28.

The angled surface 12 is shown in profile to define a straight line. The angled surface may also have an arcuate profile. The effect of the angle is that the angled surface 12 and/or the neck 20 undergo a slight elastic deformation in a radial direction when urged together.

Figure 2 shows a second embodiment of the neck 20. The internal surface 30 has an internal radiussed surface 224 at an end remote from the body of the container 22. The closure 2 and the other features of the container 22 are as described in the first embodiment.

The internal radiussed surface 224 has a profile curved with a constant radius, or the surface 224 may take any arcuate form. The angled surface 12 may also have an arcuate profile, which may be complementary to radiussed surface 224. The radiussed surface 224 and angled surface 12 may abut each other to seal the opening 28. The internal surface 224 may alternatively be chamfered at an angle complimentary to the angle of the angled surface 12, as shown in Figure 2.

The radiussed surface 224 provides a greater surface area in contact with the angled surface 12 than provided by the edge 24.

Figure 3a shows a further embodiment of the closure 2.

The closure 2 is provided with a second projection 310. The second projection 310 is an annular projection extending from the top 4 in substantially the same direction as the annular projection 10 and side walls 6. The second projection 310 is located radially outwardly and spaced apart from the projection 10. The second projection 310 is provided with a second angled surface 312. The second angled surface 312 faces radially inwardly, and away from the top 4. The angled surface 312 is shown in profile to - 10 - define a straight line. The angled surface 312 may also have an arcuate profile.

The second angled surface 312 is positioned to abut external edge 26 of the neck 20, in order to assist in the sealing of opening 28.

The second projection 310 may be the same size, or larger or smaller than the projection 10. The angled surface 312 may be orientated at the same angle from the top 4 as the projection 10, or alternatively, the second angled surface may be at a smaller or larger angle than the angled surface 12.

Figure 3a shows annular projection 10 in abutment with the internal radiussed surface 224 of the second embodiment.

Alternatively, the internal surface 30 may end at an internal edge, for example internal edge 24 as described in the first embodiment.

Figure 3b indicates that external surface 32 of the neck 20 has an external radiussed surface 326 at an end remote from the body of the container 22. The external radiussed surface 326 may have a profile curved with a constant radius, or the surface 326 may have a profile of any arcuate form. The surface 326 may also have an arcuate profile, which may be complementary to radiussed surface 312. The radiussed surface 326 and angled surface 310 may abut each other to assist in sealing the opening 28.

The radiussed surface 326 may alternatively be chamfered at an angle complimentary to the angle of the angled surface 312, as shown in Figure 3b. The radiussed - L]. - surface 326 provides a greater surface area in contact with the angled surface 310 than provided by the edge 26.

The abutment of the external radiussed surface 326 with the second angled surface 312 assists in sealing the opening 28.

Figure 4 shows an embodiment with differences from the second embodiment described above and shown in Figure 2. An annular projection 410 is provided on the top 4, the annular projection 410 having an angled surface 412 as previously described. The annular projection 410 is not a solid projection, but comprises a cavity. The annular projection 410 is hollow and defines an annular groove 405 on the top 4. The annular projection 410 may alternatively comprise a cavity which does not have an opening. The hollow projection 410 results in the angled surface 412 being more easily elastically deformable than the angled surface 12 when urged by the neck 20.

The angled surface 412 is shown in profile to define a straight line. The angled surface 412 may also have an arcuate profile, which may be convex or concave.

The internal surface 30 may have an internal radiussed surface 424 at an end remote from the body of the container 22. The closure 2 and the other features of the container 22 are as described in the first embodiment.

The internal radiussed surface 424 may have a profile curved with a constant radius, or the surface 424 may take any arcuate form. The internal radiussed surface 424 may take the form of a chamfer, having a profile of a straight line. The internal radiussed surface 424 may be an edge. The - 12 - angled surface 412 may have an arcuate profile or straight- line profile complementary to radiussed surface 224.

The closure 2 may optionally be provided with a stop 407, the stop 407 being an annular projection on the top 4 and adjacent the side wall 6. The stop 407 is positioned to be engageable with the end of the neck 20 remote from the body of the container 22, when the closure 2 is attached to the neck 20. The stop 407 has a height chosen to allow some elastic deformation of the angled surface 412, but limits movement of the neck 20 to prevent excess deformation of the annular projection 410.

Figure 5 shows a further embodiment of the neck of the container. Neck 520 is provided with an annular cavity 505 extending around the neck. The cavity 505 opens onto the end of the neck 20 remote from the body of the container 22, but may alternatively open onto the internal surface 530 or external surface of the neck. Internal edge 524 of the neck 520 is able to engage with angled surface 512 on the closure 2. When the internal edge 524 is urged onto the angled surface 512, the part of the neck supporting the internal edge 524 can elastically deform inwardly, into the cavity 505. This embodiment thus allows a relatively large elastic deformation of the neck in order to create a good seal for closing the opening.

The angled surface 512 and projection 510 may be any of the surfaces or projections described in any of the embodiments. The internal edge 524 may be a radiussed edge, or chamfered or arcuate, as described in any of the embodiments.

- 13 - The closure 2 for use with neck 520 may be provided with a stop as described in the embodiment of Figure 4, in order to limit the deformation of the neck 520.

The neck may optionally be provided with a second cavity (not shown) adjacent an external edge of the neck.

The second cavity may allow greater elastic deformation of the neck with a second angled surface in the embodiment of Figures 3a or 3b. Third and/or further cavities may be provided for the same purpose.

Figure 6 shows a further embodiment of the closure 2.

Neck 620 is the same as that described in Figure 5, having a cavity 605. Edges 611 are formed at the end of the annular cavity 605 remote from the container.

Closure 2 is provided with a projection 610, having two angled sealing surfaces 612. One angled surface 612 faces radially outwardly, and one angled surface 612 faces radially inwardly. Each angled surface is inclined at an angle of approximately 10 to 80 degrees to the central axis of the closure.

The projection 612 may be hollow, comprising a cavity to allow it to readily elastically deform. Alternatively, the projection 612 may be solid.

The angled surfaces 612 are located to each engage with an edge 611 of the neck 620. The apex of the projection 610 thus extends into the cavity 605. As the edges 611 are urged against the angled surfaces 612, the edges 611 may be urged - 14 - radially apart and/or the sealing surfaces 612 may be urged radially together.

The edges 611 may be radiussed, or may have an arcuate profile or be chamfered. The angled surfaces 612 may have a straight-line profile, or have a convex or concave arcuate profile.

Closure 2 may comprise more than one projection 610, each projection comprising two sealing surfaces 612. The neck 620 may comprises a corresponding number of cavities 605 having edges for sealing against surfaces 612. For example, the neck 630 may comprise three cavities 605, extending parallel to each other and circuniferentially spaced. The three cavities 605 will form a total of six edges 611. The closure 2 would comprise three projections 610, having a total of six sealing surfaces 612. All the sealing surfaces 612 would simultaneously engage against the edges 611 to seal the opening of the container. Furthermore, the or each projection 610 may have one, two or more sealing surfaces 612.

The closure 2 may be integrally formed as a single piece, for example by moulding. Alternatively, the closure 2 may be formed in two or more pieces, for example with the angled surface formed on an insert which is secured to the inside of the top 4.

Figure 7 shows an embodiment related to the embodiment shown in Figure 4. A closure 702 comprises an annular projection 710 provided on a top 704. The annular projection 710 has an angled surface 712 analogous to the - earlier described embodiments. The angled surface 712 is orientated at approximately 45 to the plane surface of the top 704. The annular projection 710 and top 704 are integrally formed of a material having a substantially uniform thickness over the top 704.

The annular projection 710 defines an annular groove 705 on the top 704. The groove 705 allows the annular projection 710 to be easily elastically deformable when a neck 720 of the container is urged against the angled surface 712.

The top 704 is shaped to form a stop 707. The stop 707 is an annular projection integrally formed with the top 704, and adjacent to a side wall 706 of the closure. The stop 707 is positioned to be engageable with the end of the neck 720 remote from the body of the container, when the closure 702 is attached to the neck 720.

The stop 707 is arranged so that the neck 720 can contact the angled surface 712, arid when the neck 720 is urged against the angled surface 712 the annular projection 710 can be elastically deformed by the neck 720. The stop 707 is located to limit movement of the neck 720 relative to the angled surface 712 to prevent excess deformation of the annular projection 710. The stop 707 also assists in preventing the neck 720 being splayed outwardly by the annular projection 710. The stop 707 may also prevent the closure 702 from being over-tightened onto the neck 720.

An internal groove 736 is located between the stop 707 and the angled surface 712. When the neck 720 is engaged - 16 - with the stop 707, the annular internal groove 736 allows improved elastic deformation of the projection 710, allowing the annular projection 710 to undergo a larger deformation for the same force from the edge 724 of the neck 720. The location of the internal groove 736 means that the edge 724 of the neck 720 contacts the annular projection 710 at a line spaced apart from the radially outward edge of the annular projection 710. The annular projection 710 can be more easily be deformed when contacted away from a fixed end, that spacing being provided by the internal groove 736.

The internal surface edge 724 of the neck 720 may be radiussed or chamfered in a similar manner to the surface 424 described with reference to Figure 4.

The top 704 is shaped to provide an annular shoulder 738. The shoulder 738 is located between the stop 707 and the side wall 706. The shoulder 738 extends from the restraining surface 744 at an angle to the plane of the top 704. When the neck 720 is engaging with the closure 702, the shoulder 738 is adjacent to an external surface 732 of the neck 720. The shoulder 738 is arranged to guide the neck 720 towards the stop 707 as necessary. The restraining surface 744 may alternatively have an angular lead-in to the stop 707, i.e. at tan angle to the side wall. The lead-in may alternatively be radiussed adjacent to the stop 707.

An annular restraining surface 744 extends substantially parallel to the side wall 706. The restraining surface 744 is located between the stop 707 and the shoulder 738, radially outwardly of the sealing surface - 17 712. The restraining surface 744 faces radially inwardly, substantially facing the sealing surface 712.

The restraining surface 744 limits the radial movement of the neck 720. The restraining surface 744 is radially spaced from the external surface 732 of the neck 720 when the closure 702 is initially being attached to the container. The neck 720 when attached to the closure 702 preferably deforms the annular projection 710 by a distance in a radial direction. This deformation distance is preferably greater than the radial distance between the restraining surface 744 and the external surface 732 of the neck 720. The neck 720 is maintained in contact with the angled surface 712, with the annular projection 710 deformed, even when the neck 720 splays outwardly. There is preferably an initial 0.05mm radial clearance between the restraining surface 744 and external surface 732.

The restraining surface 744 joins the stop 707 at a corner. The profile of the restraining surface 744 and stop 77 preferably supports the neck 720. The corner preferably has a radius of curvature equal to or smaller than the radius of curvature of the corresponding outer edge of the neck 720 of the container.

The top 704 is preferably formed of thicker material at its radial periphery 740. This may increase the strength of the top 704 in this area.

Alternatively, the top 704 may be formed of material having a substantially uniform thickness. Such an embodiment - 18 - is shown with part of the top 704 shown by the dashed line 760 in Figure 7.

Figure 8 shows a further embodiment of a closure. Top 804 defines an annular projection 810 having an angled surface 812. A groove 805 allows the annular projection 810 to elastically deform when a neck of a container is urged against it.

The top 804 defines a stop 807. The stop 807 is located between the annular projection 810 and the sidewall 806. The stop 807 extends substantially parallel to the top 804. A groove 805 allows elastic deformation of the projection 810 when a neck engages the stop 807. An internal groove 836 allows the neck of the container to contact the annular projection 810 away front the end of the projection 810 connected to the stop 807. This allows the projection 810 to deform more readily when the neck is urged against the projection 810.

Figure 9 shows a schematic plan view of an embodiment of the closure 2. The side walls 6 of the closure 2 in this embodiment are circular in plan view when the closure 2 is not attached to the container.

The closure 2 is provided with groups of threads or grooves 34 arranged symmetrically around the side wall 6 of the closure 2. Preferably, there are four groups of threads or grooves 34. Between each group is a region 46 of the side wall 6 which is not provided with a thread or groove 34. The threads 34 extend radially inwardly from the side wall 6 further than the side wall 6 at the regions 46. Each group - 19 - of threads or grooves may comprise one, two or more substantially parallel ridges or grooves forming a helical thread.

The discrete groups of threads or grooves 34 are separated by smooth regions 46. The regions 46 may improve the manufacture of the closure by moulding. The closure 2 may be ejected from a mould using local expansion. This allows for faster cycle time and/or a cheaper mould.

With reference to Figure 10, the closure 2 and neck of the container are dimensioned so that when the closure 2 is attached to the neck, the threads 34 are forced radially outwardly by the neck. This urges the parts of the side wall 6 having threads outwardly. The regions 46 of the side wall 6 not provided with threads are drawn radially inwardly, since the circumference of the side wall 6 is substantially constant. The closure 2 is therefore deformed when engaged to the container by relative rotation between the closure 2 and container.

When the closure is fastened to the container, the closure 2 is deformed from being circular in a plan view to the approximately squared shape shown in Figure 10. The side walls 6 in a non-deformed state have a constant radius of curvature. The outside of the side wall 6 in the deformed state defines areas 50 having a larger radius of curvature, which can be considered as flattened portions. The flattened portions 50 are generally still curved, i.e. not planar, with a radius of curvature larger than the original non- deformed closure 2.

- 20 - Between each flattened portion 50 is an area 52 of reduced radius of curvature. The areas of reduced radius of curvature can be considered as peaked areas 52. The peaked areas 52 coincide with the groups of threads 34.

The presence of the flattened portions 50 and peaked areas 52 improves the ease of purchase of the closure 2 by a user. The flattened portions 50 and peaked areas 52 allow a better grip to be obtained on the side wall 6 by a user than on a cylindrical closure. This allows the force to be appliedmore easily by a user to turn the closure relative to the container. This may be of particularly benefit to elderly people, or anyone who has difficulty obtaining a grip on a cylindrical exterior of a conventional closure.

The closure 2 may retain none, some or all of its deformity after removal from the neck of the container.

Figure 11 shows a cross section through the closure 2 along a line A-A through regions 46 shown in Figure 10. The top 4 of the closure retains a generally circular shape as the closure 2 is attached to the neck. The side wall 6 at the flattened portions 50 is forced inwardly. The amount of deflection of the side 6 is greatest in the centre of the flattened portions 50. Diametrically opposite distal ends 64 of the closure 2 are spaced closer than diametrically opposite points on the side wall 6 adjacent the top 4.

Figure 12 shows a cross section through the closure 2 along a line B-B through the threads 34. The top 4 of the closure retains a generally circular shape as the closure 2 is attached to the neck. The side wall 6 at the areas 52 is - 21 - forced outwardly. The amount of deflection of the side 6 is greatest in the centre of the peaked areas 52. Diametrically opposite distal ends 64 of the closure 2 are spaced further apart than diametrically opposite points on the side wall 6 adjacent the top 4.

The closure 2 is typically formed of a polymeric material, and in particular PLA. The material may have a cellular microstructure, for example a closed cellular structure. A closed cellular structure may be achieved by using a blowing agent, to create a foamed material.

The person skilled in the art will recognise that a variety of polymers may be used as the polymeric material in the present invention. Some other examples of polymeric materials have been listed previously.

The polymeric material of the closure may be foamed particularly adjacent the top 4 in the radially outer areas of the closure, where the top 4 and side wall 6 adjoin. This region may be thicker than other parts of the closure 2, for example for the part 704. However, the closed cellular structure is applicable to all the embodiments of the closure.

The foaming increases the resistance of the closure 2 to shattering upon an impact. The foamed material may be less brittle than a non-foamed material, increasing its ability to withstand a shock load.

The closure may be provided with a tamper evident means. The tamper evident means may be a ring which becomes - 22 - detached from the closure when the closure is first removed from the container. A shrink sleeve may be applied and heated onto the container. Any known tamper evident means may be used with the closure.

The top 704 has been described as integrally moulded.

Alternatively, the top 704 may be formed of a material of substantially uniform thickness as indicated by line 760.

The volume indicated between line 760 and line 740 may be filled with a separate piece of material. The separate piece of material may be inserted or pressed onto the top 704. The separate piece of material may by rubber, polyethylene, polyethylene foam or another material. The top 704 may have features to assist the separate piece of material to adhere.

The groove 405,705,805 and equivalent in other embodiments has been described as opening to the planar surface of the top of the closure. Alternatively, the groove may be filled with a separate filling material. The filling material may prevent dirt accumulating in the groove. The filling material is preferably deformable to allow the annular projection to deform.

The filling material may be readily deforrnable such that the annular projection is readily deformable. An example of a suitable material is polyethylene foam, although any suitable material may be used. Alternatively, a filling material may be provided which requires more force to deform. Such a material would cause the annular projection to require more force to deform. This may be advantageous to control the deformation of the annular - 23 - projection. An example of such a material is rubber, although any suitable material may be used.

In use, the closure 2 is screwed onto the neck 20 of the container 22. The closure 2 is attached to the neck 20 be means of threads and grooves 8, 34. One or more edge(s) or radiussed surface(s) of the neck engages against one or more angled surface(s) provided in the inside of the closure. The end of the neck does not directly engage against the top 4 of the closure. The closure then seals the opening 28. If a second angled surface is provided on the top 4, then the second angled surface simultaneously engages with a second edge or chamfered surface of the neck 20. The angled surface 12, 412 and/or neck 520 may be elastically deformable to improve the seal around the opening 28.

Although the closure has been described in one embodiment as having a single angled surface facing in part radially outwardly, the closure may alternatively have a single angled surface of any one of the embodiments facing radially inwardly. A radiussed surface may be provided in place of edge 26, in combination with an edge 24. Thus, any combination of one or two angled surfaces, of which one or both may be hollow, and edges or radiussed surfaces of the neck, may form part of the present invention. Any combination of convex or concave arcuate angled surfaces, or a straight-line profiled angled surfaces, with any radiussed or chamfered surface or edge of the neck may also form part of the present invention. In particular, a closure with an angled surface having a straight-line profile may be used in combination with a neck with a radiussed edge.

- 24 - Although the closure is described as provided with an annular angled surface, the angled surface may be any shape to fit the neck of the container, for example substantially S square, oval or rectangular.

The attachment means may be a hinge pivotally connecting the closure and container, i.e. a flip-top. The attachment means may also comprise a projection extending radially inwardly from the side wall of the closure engageable with a projection extending outwardly from the neck of the container, i.e. a snap-cap.

The closure has been described as deformable when screwed onto a container into the shape illustrated in Figure 10. The closure 2 may alternatively be formed in the state illustrated in Figure 10. In this embodiment, the closure 2 is not deformed when attached to the neck, but permanently maintains the shape illustrated in Figures 10 to 12.

The closure 2 has been described as deformable to the shape illustrated in Figure 10 when attached to a container.

Alternatively, the closure and container may be dimensioned such that there is substantially no deformation of the closure on attachment to a container. Alternatively, the closure may be permanently shaped as shown in Figures 10 to 12. The flattened surfaces improve the ease with which the closure can be removed from the container. The side wall of this closure is preferably formed of a material having a uniform thickness.

Claims

- 25 - CLAIMS: 1. A closure for closing an opening of a container, the

closure comprising: S attachment means for attaching, in use, the closure to the container; a sealing surface inclined to a plane perpendicular to a central axis of the closure, and located such that when the closure is attached to the container by the attachment means the sealing surface is engageable with the container.
2. A closure in accordance with claim 1 wherein the sealing surface is provided on a projection extending from the closure.
3. A closure in accordance with claim 1 or claim 2 wherein the sealing surface faces radially outwardly from the central axis of the closure.
4. A closure in accordance with any one of the preceding claims further comprising a second sealing surface, inclined to the central axis of the closure.
5. A closure in accordance with claim 4 wherein the second sealing surface faces radially inwardly towards the central axis of the closure.
6. A closure in accordance with any one of the preceding claims wherein the or each sealing surface is annular.

- 26 -
7. A closure in accordance with any one of the preceding claims wherein the attachment means comprises one or more helical threads or grooves.
8. A closure in accordance with any one of the preceding claims wherein the or each projection comprises a cavity.
9. A closure in accordance with claim 8 wherein the closure comprises a stop, such that in use the stop limits movement of the neck relative to the closure.
10. A closure in accordance with any one of the preceding claims wherein the closure is integrally moulded.
1].. A closure in combination with a container; the combination comprising: an attachment means for removeably attaching the closure to the container; the container comprising a neck defining an opening; the closure for closing the opening and comprising a sealing surface; the sealing surface inclined to a plane perpendicular to a central axis of the closure; the sealing surface located such that when the closure is attached to the container by the attachment means, the neck engages the sealing surface.
12. A closure and container in accordance with claim 11 wherein the neck of the container comprises a radiussed surface, the radiussed surface engageable with the sealing surface of the closure.

- 27 -
13. A closure and container in accordance with claim 11 or claim 12, wherein the sealing surface faces radially outwardly from the central axis of the closure.
14. A closure and container in accordance with any one of the preceding claims further comprising a second sealing surface inclined to the central axis of the closure.
15. A closure and container in accordance with claim 14 wherein the second sealing surface faces radially inwardly towards the central axis of the closure.
16. A closure and container in accordance with claims 14 or wherein the neck comprises a radiussed surface for engagement with the second sealing surface.
17. A closure and container in accordance with any one of claims 11 to 16 wherein the or each sealing surface is annular.
18. A closure and container in accordance with any one of claims 11 to 17 wherein the attachment means comprises one or more helical threads and grooves.
19. A closure and container in accordance with any one of claims ii. to 18 wherein the or each projection comprises a cavity.
20. A closure and container in accordance with any one of claims 11 to 19 wherein the neck comprises one or more cavity or cavities.

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21. A closure and container in accordance with claim 20, wherein the closure comprises a projection having at least one sealing surface; the or each sealing surface engageable with an edge of a cavity in the neck.
22. A closure and container in accordance with claim 21 wherein the closure comprises a projection having two sealing surfaces.
23. A closure and container in accordance with claim 19 to claim 22 wherein the closure comprises a stop to limit movement of the neck relative to the closure.
24. A closure and container in accordance with any one of claims 11 to 23 wherein the closure is integrally moulded.
25. A closure substantially as herein described with reference to the accompanying drawings.
26. A container in combination with a closure, the combination being substantially as herein described with reference to the accompanying drawings.
27. A closure as claimed in any one of claims 1 to 10, wherein at least a part of the closure is formed from a polymeric material.
28. A closure as claimed in claim 27, wherein the polymeric material is a thermoplastic.

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29 - 29. A closure as claimed in claim 27 or claim 28, wherein the polymeric material comprises polylactic acid (PLA) or a derivative thereof.
30. A closure as claimed in any one of claims 27 to 29, wherein the polymeric material is amorphous or at least partially amorphous.
31. A closure as claimed in claim 30, wherein the degree of crystallinity (volume) in the polymeric material is less than 50.
32. A closure as claimed in claim 31, wherein the degree of crystallinity is less than 30 %.
33. A closure as claimed in claim 32, wherein the degree of crystallinity is less than 20.
34. A closure as claimed in any one of claims 27 to 33, wherein the closure is integrally formed from the polymeric material.
35. A closure as claimed as claimed in any one of claims 27 to 34, wherein the closure is injection moulded or compression moulded.
36. A closure for closing an opening of a container, wherein at least a part of the closure is formed from a thermoplastic polymeric material comprising polylactic acid (PLA) or a derivative thereof, and wherein the thermoplastic polymeric material is amorphous or at least partially amorphous.

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37. A closure as claimed in claim 36, wherein the degree of crystallinity (volume) in the thermoplastic polymeric material is less than 50 %.
38. A closure as claimed in claim 37, wherein the degree of crystallinity is less than 30.
39. A closure as claimed in claim 38, wherein the degree of crystallinity is less than 20.
40. A closure as claimed in any one of claims 36 to 39, wherein the closure is integrally formed from the thermoplastic polymeric material.
41. A closure as claimed as claimed in any one of claims 36 to 40, wherein the closure is injection rnoulded or compression moulded.
42. A closure as claimed in any one of the preceding claims wherein the closure is sized to interact with a container such that the closure is deformable on engagement with the container, such that engagement of the closure relative to the container can flatten a curved external surface of the closure such that at least one flattened surface is formed on the external surface of the container.
43. A closure for closing an opening of a container, the closure comprising: a thread or groove engageable with a corresponding portion of a container to provide closure of the container, wherein the closure is sized to interact with the container - 31 - such that the closure is deformable on engagement with the container, such that engagement of the closure relative to the container can flatten a curved external surface of the closure such that at least one flattened surface is formed on the external surface of the container.
44. A closure as claimed in claim 43, wherein the thread protrudes radially inwardly from the inner surface of the closure.
45. A closure as claimed in 43 or 44, wherein the flattened surface is provided on an external circumferential surface of the closure.
46. A closure as any one of claims 43 to 45 comprising two or more threads, or groups of threads, such that a flattened surface is provided between the two or more threads or groups of threads.
47. A closure as claimed in claim 46 comprising four threads or groups of threads.
48. A closure as claimed in claim 45 or 46, wherein the threads or groups of threads are spaced symmetrically around the circumference of the closure.
49. A closure as claimed in claim 48 wherein the attachment means are located at four symmetrically located areas around the periphery of the closure.
50. A closure in combination with a container; the combination comprising: - 32 - an attachment means for removeably attaching the closure to the container; the container comprising a neck defining an opening; and the closure for closing the opening formed as defined in any one of claims 43 to 49.
51. A closure for closing an opening of a container, the closure comprising: a thread or groove engageable with a corresponding portion of a container to provide closure of the container, wherein the closure has at least one flattened surface formed on an external surface of a side wall of the container; wherein the side wall is formed of a material of substantially uniform thickness.
52. A closure in accordance with any one of the preceding claims wherein the closure comprises a stop, such that in use the stop limits movement of the neck relative to the closure; the closure further comprising a groove arranged between the stop and the sealing surface such that the neck contacts sealing surface at a position spaced from the stop.
53. A closure in accordance with any one of the preceding claims wherein the closure comprises a restraining surface substantially facing the sealing surface, such that when the neck contacts the sealing surface the restraining surface is located adjacent the neck to prevent substantial radial movement of the neck.

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54. A closure as claimed in claim 53 wherein the restraining surface is located radially outwardly from the sealing surface to prevent substantial radially outward movement of the neck.