GB2189228A - Screw threaded aseptic closure - Google Patents

Abstract

An aseptic closure formed by screw connection between a container component 10 having a threaded neck 11 and a cap component 12 having a top 13 and a threaded skirt 14 characterised in that the cap and container are of plastics material and in addition to any sealing present between the thread surfaces, at least two seals (22,23,24) are present in series, provided by compressively engaged annular portions of the neck and cap. The closure is adapted for a baby feeding bottle. <IMAGE>

Description

SPECIFICATION Aseptic closure and baby feeding bottle The present invention relates to an aseptic closure which is particularly although not exclusively suitable for use,in connection with baby feeding bottles. The invention also relates to a packaged kit containing disposable components which can be assembled for use in feeding babies.

Babies are particularly susceptible to bacterial infection and feeding bottles and teats require to be carefully sterilised before use and filled with sterile fluid. Water employed in the preparation of milk from powder requires in particular to be boiled before use. These preparative steps are time consuming and require a degree of skill and understanding which is not always present so that enteric disorders in babies are quite frequent.

Accordingly there has been a long felt want for a disposable feeding bottle. This has not hitherto proved practicable mainly because of the difficulty and expense of sealing sterile water or other liquid in a bottle or other suitable container amenable to feeding via a teat.

Although sterile water could be suitably sealed e.g. in a can, the feeding bottle itself would require to be sterile. Requirements to break sealed containers and transfer fluid from one to another involve an unacceptable degree of clumsiness and risk.

Special glass containers holding sterile water and capable of receiving teats have been sold to hospitals for feeding premature babies.

However these are too expensive for use by the general public.

The invention is based upon the discovery of a means whereby an aseptic closure may be formed by a screw connection between a relatively cheap cap and container of moulded plastics material which will maintain the contents of the container sterile for a sufficient period of time. By the provision of a sterile teated cap which can replace the original closure cap without disturbing the contents of the container, a disposable feeding bottle for babies becomes a feasible possibility.

The successful closure is based upon the realisation that by providing a succession of seals in series, communication between the interior and exterior of the sealed container is reduced to a negligible proportion.

According to one aspect of the invention there is provided an aseptic closure formed by screw connection between a container component having a threaded neck and a cap component having a top and a threaded skirt characterised in that the cap and container are of plastics material and in addition to any sealing present between the thread surfaces, at least two seals are present in series, provided by compressively engaged annular portions of the neck and cap.

The invention includes a baby feeding bottle filled with sterile water and aseptically closed by such a closure.

The invention also includes as an aspect a packaged kit comprising a disposable baby feeding bottle of plastics material filled with sterile water and aseptically closed by means of a threaded cap, and a sealed package containing a sterile teated cap threadedly engageable with the bottle to sealingly engage the teat between the teated cap and bottle.

In the drawings: Figure 1 is a cross-sectional view of the neck portion of a baby feeding bottle aseptically closed by a sealing cap in accordance with the invention; and Figure 2 is a similar view of the bottle fitted with a teated cap.

In Figure 1 there is shown a container component 10 in the form Qf a baby feeding bottle blow moulded from P.V.C. e.g. of specific gravity greater than 1.3 and having a threaded neck 11. The neck is shown aseptically sealed by means of a cap component 12 having a top 13 and a threaded skirt 14. An initial degree of sealing is provided by engagement of the cap threads 15 with the neck threads 16.

The cap 12 is injection moulded from a material which is softer than the material of the neck, e.g. polypropylene a specific gravity less than 1.0 which enables sealing formations on the cap, described hereafter, to be compressed or distorted upon sealing engagement with the neck.

The end portion of the neck 11 is inwardly bent to define an upwardly facing generally planar shoulder 17 which terminates in an interior flange portion 18 which protrudes upwardly from the shoulder 17 and terminates in a generally planar annular surface formation 19. In the region 20 of the junction of the flange portion 18 and the shoulder 1 7 the neck is of greater thickness than in the remainder of the neck.

The cap top interior face 21 is formed with a number of concentric annular formations.

Starting from the skirt, a first cross-sectionally tapered annular formation 22 is positioned generally centrally over the shoulder 17 of the neck which it engages compressivly in use to define a first seal. This is essentially a line seal and due to the relative softness of the cap material, sufficient deformation is assured to provide an unbroken engagement with the shoulder 17.

Spaced inwardly from the formation 22 is a plug formation 23. Although this is shown hollowed out, it is evident that the space defined within its interior surface could be solid.

The plug formation 23 has a generally cylindrical exterior surface 23a which in use engages with the extended cylindrical interior neck surface 18a defined by the flange 18 and the thickened junction portion 20 of the neck. The plug formation 23 may be very slightly in wardly tapered to assist a tight sliding en gagement with the generally cylindrical neck interior surface 18a.

Closely adjacent to the plug formation 23 is a cross-sectionally tapered annular formation 24 on the cap top interipr face which protrudes only slightly in the form of a bead. In use it sealingly engages the planar surface 19 of the flange 18 of the neck. Like the seal formed by formation 22, this third seal is essentially a line seal in which the cap material is deformed by compression to ensure conti nuity of engagement.

It will be apparent that in addition to the threads 15, 16, three seals are provided in series, the outer two being line seals and the inner a surface-to-surface seal. At each seal, communication from outside to inside is reduced by a significant factor and it has been found that overall communication is reduced to a negligible or unmeasurable amount. Although three seals are shown in Figure 1 in addition to the threads, it is considered that sufficient sealing would be possible utilising only two seals in series. Thus in Figure 1 the protrusion 24 could be omitted although it has been found to significantly assist e.g. in the retention of gases dissolved under pressure.

A suitable P.V.C. material for the bottle is Dorlyl (Trademark) FC35. This is quoted as having a specific gravity of end product measured under ASTM D 792 of 1.32 and a SHORE D hardness measured under 180 R 868 of 72. The permeability to oxygen at 20"C and 60% relatively humidity measured under ASTM D 1434 is 2.5 cm3mm/m224h.bar. The Izod impact strength under 1SO R 180 is 70 J/m at 23"C.

A suitable material for the cap is Lacqtene (Trademark) P 3120 MN 1 polypropylene. This is quoted as having a density measured under ASTM D 1506 of 0.905 g/cm2 and having a comparable Izod impact strength (1SO R 180) at 23"C of 40 (J/m).

By forming the bottle by blow moulding, the bottle neck can be held to a closed tolerance on size and roundness which assists the plug seal in the neck bore. At the same time, during the blow moulding process, the bottle neck is trimmed. It has been found possible to hold this to a closed dimensional tolerance to produce the planar surface 19 on the flange of the neck.

Various bottles and caps were subjected to relatively severe tests as follows.

Carbon dioxide test In this test a bottle is half-filled with carbonated water, the cap fitted and the bottle inverted to determine whether the cap can withstand the pressure of carbonated liquid.

Submersion test In this test a bottle is filled with acid washed sand (in order to weight it). The cap is fitted and the bottle is then submerged in water to determine if the cap will allow entry of water into the bottle. The bottle is checked daily for one week.

Sterility test A bottle and cap is sterilsed by soaking in hydrogen peroxide for approximately 10 minutes. The items are then rinsed out with sterile deionised water. A sterile broth is then added and the caps fitted and the bottles inverted. Any microorganisms entering into the bottle cause the broth to become cloudy.

Original tests were conducted without the central seal 24 and using a relatively hard material for the cap. The three tests failed in all cases.

After replacement of the cap with the material above described but without the central seal at 24 there was a failure of the carbon dioxide test after 5 minutes, some failure of the submersion test but no failure of the sterility test.

Utilising the bottle and cap as shown and described with the central seal formed by the protrusion 24, the closures survived all tests.

Microscopic examination revealed that the protrusion 24 was slightly indented indicating that the seal had been compressed against the flange surface 19.

Turning to Figure 2, the bottle 10 with its neck 11 is seen to be identical with that of Figure 1. The sealing cap of Figure 1 is shown replaced by a teated cap 30 in which the lower portion of the skirt is similar to that of Figure 1 but the top and upper portion of the skirt are modified. The skirt 31 is extended upwardly and formed with an inward annular flange 32 through which protrudes the body 34 of a rubber teat 33. The teat 33 has a reinforced generally toroidal rim 35 of substantially solid cross-section. The flange 32 has a generally downwardly and inwardly sloping interior surface 36 which terminates in a downwardly protruding bead 37.

The end of the flange 32 compressibiy engages against the neck 38 of the teat at the junction of the body 34 and the rim 35. The rim 35 is compressibly engaged between the flange surface 36 and the shoulder 17. The flange 18 of the neck is utilised in assisting the shoulder 17 in forming an almost continuous circular enclosure of the rim 35 of the teat and also in producing a sealing engagement of the neck 38 of the teat against the bead 37.

With the teat secured as shown, there is not only complete sealing of the teat against loss of fluid or ingress of contaminants, but a mechanically secure containment of the teat against the tugging of the baby.

In use, a baby bottle generally as shown will be sterilsed and filled with sterile water e.g. by the method described in my concur rent patent application no. 86 09536 (J.17670) and sealed by means of the cap 12 of Figure 1 under sterile conditions. The filled bottle will then be packaged together with a teated cap 30 as shown Figure 2 which has been enclosed in a sealed package and subjected to gamma radiation for sterilisation.

If it is desired to feed the baby with water alone, all that is necessary is to unscrew cap 12 and replace it by the teated cap 30. This simple manoeuvre should effectively prevent any contamination of the resulting feeding bottle. Should any contamination have reached as far as the flange 18 of the bottle, this will be effectively sealed out by the rim 35 of the teat.

If it is desired to feed the baby with e.g.

milk, powdered milk can be inserted through the neck of the opened bottle e.g. utilising a sterile funnel in a sealed package which may be included with the general package. Naturally other appropriate concentrates could be added. After use the whole of the contents of the original package should be destroyed.

The invention, together with the invention of my aforesaid concurrent application, enables the bottles to be produced by relatively simple blow moulding machines of relatively low capital cost and which operate at high speed, when compared with expensive and slow machines conventionally used for sterile filling of e.g. medicines. Such machines would rule out the sale of disposable baby feeding units on the ground of cost. Relatively cheap materials are utilised and the bottles and caps can be produced at a rate of over 10,000 units per hour.

Claims (21)

1. An aseptic closure formed by screw connection between a container component having a threaded neck and a cap component having a top and a threaded skirt characterised in that the cap and container are of plastics material and in addition to any sealing present between the thread surfaces, at least two seals are present in series, provided by compressively engaged annular portions of the neck and cap.

2. A closure according to claim 1 including three seals in series.

3. A closure according to claim 1 or claim 2 wherein at least one said seal is provided by compression of a cross-sectionally tapered annular formation on the cap top interior face against a generally planar shoulder on the neck.

4. A closure according to any preceding claim wherein at least one said seal is provided by surface to surface engagement between a generally cylindrical exterior surface of a plug formation on the cap top interior face and a generally cylindrical interior neck surface.

5. A closure according to claim 3 and claim 4 wherein the two formations on the cap top interior face are spaced apart.

6. A closure according to any preceding claim wherein at least one said seal is provided by engagement of an annular portion of the cap top interior face against an annular formation at the end of the neck.

7. A closure according to claim 6 as dependent on claim 5 when said annular portion of the cap top interior face is intermediate said two formations in the cap top interior.

8. A closure according to claim 6 or claim 7 when said generally annular portion of the cap top interior face is a formation of tapered cross-section and the annular formation at the end of the neck is generally planar.

9. A closure according to claim 8 as dependent on claim 3 wherein said neck comprises an interior flange portion protruding from said generally planar shoulder which flange portion partly defines said generally cylindrical interior neck surface and defines said planar annular formation at the end of the neck.

10. A closure according to claim 9 wherein the neck is of greater thickness in the region of the junction of the flange portion and shoulder than in the remainder of the neck.

11. A closure according to any preceding claim when the cap is of sufficiently softer material than the neck that sealing formations on the cap are compressed or distorted upon sealing engagement with the neck.

12. A closure according to any preceding claim wherein the cap is of polypropylene.

13. A closure according to any preceding claim wherein the neck is of P.V.C.

14. A closure according to any preceding claim wherein the cap is of polypropylene of specific gravity less than 1.0 and the neck is of P.V.C. of specific gravity greater than 1.3.

15. An aseptic closure substantially as described herein with reference to Figure 1 of the accompanying drawings.

16. A baby feeding bottle filled with sterile water and aseptically closed by means of a closure according to any preceding claim.

17. A package comprising a baby feeding bottle according to claim 16 and a sterilepackaged teated cap the cap being threadedly engageable with the bottle.

18. A package according to claim 17 wherein the bottle is as specified in claim 9 and the teated cap has an annular flange through which the teat body protrudes, the flange having a downwardly inwardly sloping interior surface, the teat having a reinforced rim of substantially solid cross-section compressibly engageable in use between said flange and said shoulder and with part of the teat sealingly engageable in use between said neck interior flange portion and the end of said sloping flange.

19. A package according to claim 18 wherein the end of said sloping flange is formed with a downwardly protruding bead engaged or engageable in the junction of the rim and the body of the teat.

20. A package according to claim 17 wherein said teated cap is substantially as described herein with reference to Figure 2 of the accompanying drawings.

21. A packaged kit comprising a disposable baby feeding bottle of plastics material filled with sterile water and aseptically closed by means of a threaded cap, and a sealed package containing a sterile teated cap threadedly engageable with the bottle to sealingly engage the teat between the teated cap and bottle.