HK1036040B - Closure, bottle having the closure, and process for bottling fluid - Google Patents

Description

Closure, bottle using the closure and method of bottling a liquid

Technical Field

The present invention relates to liquid packaging.

The present invention relates primarily to packages using thin-walled extrusion blow-molded plastic bottles for liquids, such as milk, which need to be filled and closed in a resealable manner.

The present invention also relates to reclosable cap-like closures for use with plastic bottles or synthetic material cans and, more particularly, to such closures which provide tamper-evidence.

In the following description, the problem of packaging milk is specifically mentioned. However, it should be appreciated that other pourable liquids, such as fruit juices, have similar packaging problems. However, the present invention relates only to liquids which do not need to be packaged in a pressure-tight manner. Therefore, the problem of packaging carbonated beverages is not mentioned.

In one aspect, the invention is also particularly directed to packaging forms where container weight is an issue, and thus particularly to thin-walled blow-molded plastic bottles.

In another aspect, the present invention relates to a reclosable cap-like closure which will show when tampering occurs.

Background

Generally, milk is packaged in gable-top paperboard containers, which are difficult to open and cause numerous customer complaints about milk spillage and difficulty pouring. Such fibrous board is only suitable for packaging liquids with a volume of not more than 1.5 litres.

To solve these problems, blow molded plastic polyethylene bottles have been used. These bottles are provided with a resealable cap. Such resealable caps are typically injection molded products. Since weight is important when packaging liquids such as milk, these lids must be light in weight. A weight of 2 to 4 grams is usually the maximum allowable limit.

There is also a fundamental problem in achieving a good seal between the neck of the blow-molded bottle and the injection-molded plastic closure. This is due to the tolerances of the neck being 0.3mm in number and the tolerances of the moulded product, for example the cap, being 0.1 mm. This means that when the cap is fitted to the neck, a portion of the cap does not close tightly. For all designs of lid this can lead to difficulties in assembly on the production line and leakage problems for retailers and wholesalers. If the cap is too tight, the ultimate consumer may experience difficulty in resealing the bottle or opening the cap too tightly for the first time.

To address these problems, many injection molded cap designs have been made. For example, in one type of cap design, known as a valve seal or flexible seal closure, a stopper is provided in the cap which is pushed into the neck of the bottle and a multiple start thread is provided on the inside wall of the cap skirt. This type of lid provides a double seal. The stopper provides a seal with the inner wall of the neck. The second seal is provided by an inwardly projecting ridge on the thread on the inner wall of the cap which forms a seal with the outer wall of the neck. A flexible tab at the lower edge of the lid can provide tamper evidence for this type of lid. For a lid made of low density polyethylene, the lid can be pried together in a chain, and thus this form of tamper evidence is not very reliable.

Another design, known as Induction Heat Sealing (IHS), provides a foil gasket that is placed on the bottom of the lid. In a production line, a liquid-filled bottle with a cap is passed through an induction heat source which melts the foil onto the neck of the bottle. When the consumer unscrews the cap, the bottle neck remains sealed by the foil. The foil seal is removed in a separate operation. Tearing the seal can result in a very small amount of plastic material forming on the neck surface of the bottle, which can prevent a good seal from being formed when the cap is replaced after the first opening. The parameter settings of the bonding process using induction heat sealing are critical in order to achieve a bond that is weak enough to enable the user to tear the foil, but strong enough to maintain a good initial seal with the container neck. The presence of the foil means that no stopper can be provided, so that the reclosability of the lid is poor and the sensitivity to leakage in the user's home is increased. Such a lid is also relatively expensive, since the tearable foil adds up to 20% to the cost of the container.

Another set of problems can arise during the bottling and sealing line of bottles. Since the maximum linear speed of the milk is defined by the speed at which the milk starts to froth, the rate of filling depends on the size of the nozzle used to inject the milk into the bottle. The size of the nozzle is defined by the size of the neck. For a typical milk container, this is 38 mm. A larger neck allows for faster filling, but presents greater sealing problems and requires a larger cap.

Herein, the term blow-molding refers to extrusion blow molding rather than stretch blow molding. In many modern production lines, blow molding plants are located adjacent to dairy plants. This allows the bottle to be formed, filled and sealed in a single continuous process. The most complex stage in blow molding is to balance each parison and control the distribution of the ingredients. The parison is then expanded against the walls of the temperature-regulating mold, causing it to solidify to assume the shape of the mold cavity. In one conventional design of blow molding machine, a set of molds is reciprocated between an extrusion station and a blow station. The number of die heads provided is substantially equal to the number of die cavities in the set or a fraction thereof. These die heads are fed by a manifold which generally causes an imbalance in the delivery of the plastic material to each of the final parisons. This process has certain difficulties in continuously forming the neck of a thin-walled container to achieve an optimum tolerance of +/-0.3mm with repeatable accuracy. To achieve good performance with a valve sealing closure, it is necessary to form a fully circular neck bore with a minimum amount of ovality in both the bore and the threaded portion. Two processes are known to achieve the above results in multi-cavity blow molds. They are either "drawing" processes, where a core blowing pin is lifted by a shear steel device to cut a circular hole in the neck of the bottle, or "tamping" processes, where a core blowing pin is forced down into a shear steel device. The draw-off has the disadvantage that the neck member is structurally weak and when the hole is relaxed for too long, it can cause a poor seal with the valve sealing closure, thereby causing leakage. However, the tamping process gives a very strong neck, but this has the disadvantage of being heavy, with the additional cost of ovality of the neck and loss of material. Ovality causes poor sealing with the valve seal closure. Neither of these processes is suitable for molding the pour lip structure on the neck of a bottle. For drawing finishing it is almost impossible to mold a pouring lip structure, for tamping finishing a large amount of extra material is required, and molding is almost impossible to prevent large ovalities and defects in the hole.

The above-described process involves molding equipment manufactured by companies such as Uniloy, Techne, and Bekum.

Another type of machine manufactured by companies such as Graham Engineering and Uniloy employs a process commonly referred to as rotary blow molding, which is particularly well suited for use in on-site blow molding plants. Unlike the previous process, the convolution produces only one parison at a time when extruded from one die head. The module is mounted on a rotating wheel and passes around the parison joint as the wheel rotates. A needle-like device pierces the parison and expands the plastic until it hardens against the wall of the mold. Rotoblow molding provides a high degree of control of the material in containers produced in this manner. The assembly time of such a machine is greatly reduced, since only one die head has to be fitted.

Where the inner wall of the neck provides a partial seal, it may be necessary to provide a separate finishing station, the neck being finished by reaming or by punching. The finishing step may generate chips which may lead to dangerous situations where chips may enter the interior of the bottle and render the bottle unsuitable for immediate filling.

For products that require large quantities for sale through retail outlets, such as milk, it is highly desirable to minimize the weight of the package. This has resulted in larger containers and thinner walls. The wall thickness of blow-molded High Density Polyethylene (HDPE) is typically 0.4 to 0.6 mm. This resulted in a 4 pint (2.27 liter) bottle having a weight of about 40 grams. Therefore, any means for solving the technical problems cannot increase the weight of the bottle and preferably can reduce the weight of the bottle.

For cardboard boxes, it has been proposed to provide a separate pouring spout device which is secured to the cardboard box. An example is described in WO-A96/14249(Capitol Spots Inc.). The pour spout includes a lid and an integral inner membrane seal and is mounted to the outer wall of a liquid-filled carton. The container may have a scored portion so that when the inner film seal is removed, it creates an opening in the scored portion of the container wall through which the contents of the container can reach the pour spout. This device is not suitable for use with a plastic container where it is impractical for a user to tear open an opening in a plastic-walled container. Cardboard boxes typically have one continuous inner liner. This type of pour spout must be attached to the carton prior to filling and cannot be used to fill the container.

GB-a-2108464 (container company, usa) describes an end closure in which a film is sandwiched between the container body and the edge portion of the end member and adheres them to one another. The film has a heat-activatable sealing material, for example polyethylene, polypropylene or other similar types of material, on both sides. The reader is advised to use this type of closure with a container which may be all plastic or a combination of cardboard and plastic material. The exact method of producing the container body and the end element is not described. The specification also does not mention a method of filling the final container. The specification mentions in particular the use with cylindrical cardboard containers. Such containers will typically be filled from the bottom after the open end has been completed and sealed.

US-A-24,815,618(Gach) shows A tamper-evident closure for bottles designed for dry objects. The base has a skirt that mates with the neck of the bottle and defines a pour spout. A foil is interposed between the neck and an adjacent surface of the upper end of the base. A pull ring is attached to a disc which is connected to an opening in the upper end of the base by a frangible metal web. The disc is bonded to a foil. The closure is opened by pulling on a tab which tears the foil from the pouring spout. In an alternative embodiment of the Gach invention, the disc is not attached to the base and the foil is provided with a circumferential score line to facilitate tearing at the inner surface edge of the pour spout. In either embodiment, it is not possible to produce an opening with smooth edges. This will not be a problem when the bottle is used for tablets or the like, but the edge of the foil torn in the pouring spout is not suitable for pouring liquid. The material of such bottles is not disclosed.

Although these documents serve as the most relevant prior art, they do not represent an inherent starting point for attempting to solve the problems associated with thin-walled plastic bottles, in which teaching has hitherto been given without exception that the bottle body and the neck of the bottle are integrally formed.

Thus, although it is known in GB-a-2108464 to produce a separate element defining a neck, the long-standing technical problem of using this method to solve effective resealing of thin-walled blow-moulded plastics containers for containing liquids has not been achieved to date and therefore cannot be considered obvious.

Disclosure of Invention

The present invention provides a thin walled plastic bottle comprising a gas permeable extrusion blow moulded body and an injection moulded neck and cap means adapted to fuse with said body after said body is filled with a liquid, wherein a foil is interposed between said body and said neck and cap means; the cap is fitted to the neck so as to provide a resealable closure without leakage.

This configuration has many advantages. The neck and the cap will fit together in a reliable sealing manner since both elements are formed by the same manufacturing technique, preferably injection moulding, which means that both elements will have the same tolerances. The neck and cap devices can be supplied by another factory that can produce these devices in a sanitary environment. Any prior lid design can be used.

The bottle body to which the neck and cap device is mounted may have a relatively wide opening through which it can be filled, thus increasing the speed of filling.

The present invention also provides a leak-free closure comprising an injection moulded neck and cap device and a foil for use with the body of the aforementioned thin-walled plastic bottle or other container, wherein the neck and cap device comprises a base portion fitted to the body; said foil being sealed to said base of a neck and cap assembly, said neck having a removable annular flange connected to a pull ring and secured to said foil; said removable annular flange being separated from said base by a frangible region; a plurality of associated teeth are formed in the base at or adjacent the frangible region, each tooth having a saw-shaped profile which is inclined inwardly towards the centre of the base, the foil being torn by the teeth on movement of the tab.

In a preferred embodiment of the closure, the cap includes a closure plate and an associated skirt, and the base has a reduced strength annular groove which is concealed by the cap skirt when the closure is sealed. With this arrangement, any attempt to pry the base away from the neck of the bottle will result in damage to the lid-like closure due to the lever force causing the base to break at the reduced strength groove.

The present invention also provides a bottle associated with the prior art described in Gach, comprising a body having an opening, a neck and cap device comprising a skirt adapted to cooperate with the mouth of the bottle and defining a pouring spout, and having a pull ring connected to a movable element located at the base of the neck which rests on the upper surface of the opening; and a foil sheet is interposed between the surface and the base and fused thereto so that removal of the tab and the removable element causes at least part of the foil to be removed and the pour spout to be opened; wherein the removable element comprises an annular flange which is separated from the remainder of the base by a frangible groove, said groove defining a plurality of associated teeth, each tooth having a saw tooth shape which is inclined inwardly towards the centre of the base so that when the tab is pulled, the foil is torn by the saw tooth.

The use of an annular flange rather than a disc as described in Gach allows the neck assembly to be moulded as an assembly by means of a mould which can be spaced along an axis passing through the centre of the tab and flange. The serrated teeth tear the foil completely, ensuring that it is removed with the tab, thereby allowing liquid to flow freely out of the pour spout.

In addition, the foil is used to seal the opening while the neck and cap assembly is fused to the opening in a single heat sealing operation. This results in a more reliable sealing of the filled bottles, avoiding any leakage during wholesale and retail sale.

The closure is suitable for use with thin-walled plastic bottles and synthetic cardboard boxes or containers of any other material to which the closure can be fitted.

The invention also provides a method for bottling liquid, which comprises the following steps: extrusion blow molding a thin-walled bottle body having an opening; filling the bottle body; fitting a neck and cap device, the base of which is covered by a foil and the size of which corresponds to the mouth of the bottle, onto each filled bottle, wherein the cap is fitted to the neck to provide a leak-free resealable closure; heat sealing the bottle body to the neck and cap device.

The term thin-walled as used herein means having a wall thickness of 2mm or less and preferably in the range of 0.1mm to 1.0 mm. Containers with wall thicknesses less than 0.1mm may not have the structural integrity necessary to maintain their shape when filled with liquid. For a milk container with a capacity of up to 6 pints (3.41 liters), a wall thickness of 0.4 to 0.6mm is suitable.

Drawings

For a better understanding of the invention, an embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a side view of an opening portion of a first embodiment of a bottle body;

FIG. 2 is a perspective view showing an opening portion of the bottle body shown in FIG. 1;

FIG. 3 is a top view of the opening of the bottle body shown in FIG. 1;

FIG. 4 is a cross-section through one side wall at the opening of the bottle body shown in FIG. 1;

FIG. 5 shows a cross-section through a neck and cap device mounted to a second embodiment of the bottle body;

FIG. 6 shows a perspective view from below the neck;

FIG. 7 shows a plan view from below the neck;

FIG. 8 shows an enlarged view of a portion of the bottleneck as viewed from below;

FIG. 9 shows a perspective view from above the neck;

FIG. 10 shows an underside plan view of a cover;

figure 11 shows a section through the cover.

Detailed Description

The body 2 has an open portion 4 which is integrally formed in a single blow molding operation. The shape of the rest of the body is not shown as it may take any suitable shape. For example, it may be square, rectangular or circular in cross-section and may have an integrally formed handle as part of the bottle shape.

The profile 6 of the opening is best shown in fig. 4 and includes a vertical wall 8 adjacent a recess 10 which merges with an inwardly directed horizontal base flange 12. The purpose of the slots 10 is to make the structure of the opening stronger and resist pressure when top loaded during later attachment of the neck and cap assembly. When used in a filling process, it also serves to locate the open portion of the neck assembly.

The body 2 and its shaped mouth portion 6 are formed by moulding, in any suitable conventional extrusion blow moulding process, a parison of high density polyethylene or other suitable plastics material is expanded in accordance with the mould. If the blow molding is performed on a rotary machine, the small V-shaped notch 14 in the flange 12 shown in FIG. 3 will be formed. These notches are usually removed in a second stage, which are trimmed off by reaming or by punching, after the parison dome has been cut off from the container leaving the mouth 6. The present invention eliminates the need for such reaming and finishing. These or any other irregularities in the profile in the mouth portion do not have to be removed when fusing the neck portion to the container profile 6.

The mouth of the bottle shown in fig. 5 has a modified profile relative to the embodiment of the bottle shown in fig. 1 to 4. The profile of the bottle mouth shown in figure 5 defines a narrow shelf 15 around the mouth on one of the troughs 10. The shelf allows the neck of the neck and cap assembly to be placed on the bottle during assembly prior to full engagement of the neck with the bottle body. The presence of the shelf 15 allows the bottles to be moved along the assembly line without the neck and cap assembly falling off when the neck is placed on the bottle.

The neck 16 is shown in figures 5,6, 7 and 9. The neck includes an annular sidewall 18 supported on a base 20 which is fitted to the bottle body and which in this embodiment includes a flat portion which covers the mouth of the bottle and a skirt which conforms to the shape of the neck. It will be appreciated that other forms of base will be required when the closure is used with other forms of container. For example, a base for use with a synthetic container can end may employ a flange that projects from a flat portion that covers the can opening. Such flanges may be attached to the paperboard material by a melting process or other known methods.

The side wall 18 forms a pour spout for the container and terminates in a projecting pour lip 22 which is slightly inclined to the pour edge. In the illustrated embodiment, the annular side wall 18 defines a slightly outwardly projecting curved profile that tapers toward the pouring edge and terminates at a point where the outer and inner surfaces of the wall converge. The profile here must be moldable in a reproducible manner. An accurate position will give particularly good control and allow very small amounts of liquid to be controllably poured from the pouring opening. This exact position cannot be blow molded without weight or cycle compensation and therefore represents a significant improvement over blow molded pour lips. On the inner surface of the annular side wall 18 there is an annular corrugation 24 arranged below the pouring lip. The annular corrugation 24 is provided for interfitting with a corresponding corrugation 56 on the plug of the cap in the manner described hereinafter.

Opposite the pouring lip, the side wall 18 meets a flat portion 26 of the base 20. The flat portion 26 covers the opening portion of the bottle body and includes an outer annular flange 28 and an inner annular flange 30, the outer annular flange 28 projecting outwardly from the side wall 18. The inner flange 30 is separated from the remainder of the neck assembly by an annular gap which is spanned by a number of mutually spaced bridges 34 which connect the inner annular flange 30 to the inner surface of the side wall 18. The gap with the bridge 34 forms a frangible region 32. The bridges 34 are equally spaced from each other throughout the frangible zone. The bridge 34 is tapered in its plan view, as best seen in fig. 8. Bridge 34 meets inner annular flange 30 at its widest point and meets side wall 18 at its narrowest point. This ensures that all bridges 34 will break at their weakest portions adjacent the side walls 18. In another embodiment, the frangible region may be provided by a thin layer of plastic. However, the use of a bridge reduces the removal force and makes it easier to control by adjusting the number of bridges and the narrowness of each bridge at its junction with the side wall.

As shown in fig. 5, the outer edge of the inner flange 30 and the inner edge of the outer flange 26 have angled side walls that define, with the gap and the bottom of the side walls 18, a recess in which the frangible region 32 is disposed.

A series of spaced apart point-like teeth 36 depend downwardly from the bottom of the recess. Each tooth 36 shown in fig. 7 and 8 is triangular in plan view and has a saw-tooth shaped cross-section as shown in fig. 5. The teeth 36 are inwardly inclined toward the center of the base. It will be appreciated that the pitch of the teeth may vary from that shown in the figures. In embodiments where the frangible portion is provided by a thin plastic film, the teeth may be provided on that film.

The inner flange 30 has three thin runners 38 extending from the inner surface to the center. This configuration allows the neck assembly 16 to be centrally molded, which provides a more uniform distribution of plastic material during the molding process. If side-spraying is used, it is not necessary to provide a runner.

One inner surface of the inner flange 30 supports two proximate legs or posts 40 formed on either side of the runner 38. The posts are erected and bent until they meet to form a pull ring 42. The pull tab 42 is formed with a tear-off cross-section to facilitate removal from the molding tool. The user's fingers are inserted into the tab and a force may be applied to the leg 40. The applied force causes the frangible portion to break away from the connection point in both directions simultaneously to open the closure. The presence of two posts reduces the risk of the tab 42 breaking away from the flange 30. The inner lower edge of the pull ring 42 preferably has a curved rather than a pointed edge in order to prevent the ring from cutting into the user's finger during the pulling operation.

A skirt 44 extends around the side wall 18 and depends from the outer flange 28 of the base 26. The skirt 44 terminates in an inwardly projecting rib 46 which is adapted to engage a groove 10 in the mouth profile 6 of the bottle body 2.

An annular reduced strength groove 48 is formed in the upper surface of the outer flange 28 and toward the outer edge. The groove 48 provides a reduction in structural strength so that if an attempt is made to lever the neck 16 off by leverage between the skirt 44 and the wall of the bottle 8 after the container has been assembled, the skirt will separate from the flat portion 26 indicating that the closure has been tampered with.

In another embodiment (not shown), the annular sidewall 18 may be provided with a shoulder so that the pouring spout of the neck portion closed by a cap 50 may have a smaller diameter than the opening portion of the bottle body.

The design of the side walls of the neck 16 and the pouring spout depends on the type of cap used to complete the neck and cap device. The cap 50 in the illustrated embodiment is of the valve seal type, which provides a press fit. It will be appreciated that the neck may be used with a screw thread on a cap and for this purpose a screw thread or multi-start thread may also be formed on the outer surface of the side wall 18 to co-operate with a screw thread formed on the inner wall of a cap used therewith.

The cap 50 shown in fig. 10 and 11 is an injection molded component that includes a cover plate 52 having a cylindrical inner plug 54 attached thereto. A cylindrical plug 54 extends vertically downward from the cover plate 52. An annular corrugation 56 is formed along the outer surface of the plug. The corrugations 56 cooperate with the corrugations 24 of the annular sidewall 18 of the neck 16 to retain the cap 50 on the neck. Below the corrugations 56, the plug wall tapers inwardly to facilitate insertion into the open portion of the neck.

A depending outer skirt 58 is attached to the edge of the cover plate 52. Skirt 58 has a substantially vertical region 60 adjacent to cover plate 52 that meets with a flared region 62. The free edge of flared region 62 opposite closure 52 aligns itself with the edge of neck skirt 44 outward of the reduced strength channel 48 so that there is an unfolded profile of the closed neck and closure assembly. The depth of the skirt 58 is such that when the cap is fully mated with the neck 16, the rim just reaches the upper surface of the flat portion 26 of the neck 16. The gap in the neck and cap assembly is preferably 0.5mm before it is fitted to the bottle body.

The profile of the flared region 62 allows the skirt to flex when subjected to downward pressure applied to the cap during assembly. It will also be appreciated that the alignment of the skirt 58 with the outer edge of the neck fitment ensures that downward force applied to the cap is transmitted through the skirt 58 to the skirt 44 of the neck fitment and thus to the body of the bottle 12. This minimizes damage to the pour spout and recess structure during assembly of the neck and cap device and during resealing of the bottle.

An annular corrugation 64 is located inside the skirt 58 of the lid closure but spaced from the top of the vertical region 60. The purpose of the corrugations 64 is to provide a seal with the underside of the pour lip 22.

The cap 50 is press fit to the opening of the pour spout. Which is sufficiently flexible so as not to deform the pouring lip during the sealing and resealing operations. The slightly curved profile of the annular side wall 18 maintains sufficient strength to guide the stopper of the cap as it is pressed. For the design shown in fig. 5, there are two sealing positions between the cap and the neck. The first sealing position is between the annular corrugation 64 and the underside of the pouring lip. The second sealing position is between the co-operating annular corrugations 24, 56 on the side wall 18 and the plug 54 respectively. When the cap is mated with the neck, the bending of the annular corrugations as they contact each other creates a sound indicating that the seal has been formed and the cap is properly installed. The sealing of these two locations is very effective in eliminating leakage. Since the neck assembly and the cap are all injection molded components, they can be precisely molded. This ensures that a good, repeatable fit can be provided.

As shown in fig. 9 and 10, a horizontal tab 66 projects from a portion of the lower edge of the skirt 58. The tab allows the user to pry the cap from the neck when opening the container. The tab 66 has an arcuate shape in plan view which provides a relatively large contact area with the skirt 58. Keeping the protrusion of the sheet to the minimum necessary to be lifted by the fingers. The foil must be relatively inflexible. Given a relatively large area of attachment of the flap to the skirt, flexibility is reduced. Since the tab is relatively inflexible, it is easier for the user to eject the cap from the neck of the bottle by a simple turning or prying operation when it is touched by a finger.

The use of a skirted cap conceals the weakened slot 48 which covers the entire upper surface of the neck finish when the bottle is displayed, the slot providing tamper evidence for the neck finish. If an attempt is made to pry the skirt from the bottle, the seal will be broken and the custodian will be immediately alerted to the attempted tampering with the bottle. This type of tamper evidence is considered more effective and provides a higher degree of user confidence in response to a failed tamper attempt.

In order to minimize the weight of the cover; the plastic material from which it is molded may be foamed. This will make it strong enough to be used, but also light in weight to minimize overall weight and correspondingly transportation costs.

The neck is fitted to the body of the bottle with an intermediate sealing foil 70. Foil 70 may be a polymer foil or a polymer foil laminated to aluminum foil or aluminum. The foil is chosen so that both sides of the foil are adhesive and can be torn off with little force. Any material commonly used to provide a heat-sealable foil in existing plastic baby bottles may be used. To facilitate tearing, a foil that is thinner than prior art tearable seals is necessary. Each layer of polymer must be thin enough so as not to interfere with the tearing of the foil. A 12 to 25 micron aluminum foil having 15 to 30 micron or smaller polymer layers on both sides thereof is easily torn in use and maintains the necessary seal with the lid. When an aluminum layer is used, small holes may be provided in the aluminum layer to allow the polymer to pass through during the heat sealing process to form a bond between the bottle body edge 12 and the adjacent surface of the neck base 26. The foil is preferably provided already glued to the bottom of the neck and cap assembly. The neck and cap assembly with the foil is then transported to a filling plant.

During heat sealing of the foil to the lower surface of the flat portion 26, there is some flow of plastics material into the recess between the inner and outer flanges 30, 28. The width of the recess is important because this flow of material must not submerge the teeth 36. During induction heating, the pour spout 18 also flexes to the extent that the edge of the skirt 58 of the lid 50 will contact the upper surface of the flat portion 26.

The neck and cap are preferably both injection molded plastic components. Since they are all manufactured by the same method with the same tolerances, the seal between the neck and the cap will be good. The neck and cap assembly is supplied to a bottling plant ready for assembly, testing and sterilization.

The details of the injection molding process and the detailed form of the mold are not described herein as they would be apparent to one skilled in the art.

Filling process

The described bottle and cap arrangement can be used in various ways in the filling plant of a bottling plant. The bottles may be supplied to a plant ready for forming, but this results in a large number of transports and it is preferred to form the bottles in a blow moulding plant adjacent to the plant so that they can be formed and filled on a continuous production line. The absence of further finishing and finishing of the interior of the mouth of the bottle body makes this design of bottle particularly suitable for this process.

In a preferred embodiment of the process, the bottle bodies are blow molded using a rotary machine having a series of molds adapted to pass under a single mold head for supplying a predetermined amount of plastic material to form a parison that is subsequently expanded to form the bottle bodies. Such rotary machines are commercially available and require only modification of the mould to define the required opening profile 6, rather than a more conventional neck.

Liquid such as milk is filled into the bottle through the opening.

In aseptic packaging, the foil 70 will be sprayed with a sterilising solution, such as a water/paractic acid mixture, in order to sterilise the surface of the foil which will be adjacent to the milk in the filled container. Such a disinfectant solution is under the trademark OXONIA. Other sterilization methods, such as radiation, may also be used, but are relatively expensive.

The sterilized neck and cap assemblies provided with the foil are fed through a chute to a pick and place apparatus which rotates each neck and cap assembly and places it onto a filled bottle. The skirt 44 is clamped against the outer contour 6 of the bottle mouth with the foil sandwiched between these two elements. In the next process step, the neck assembly 16 is glued to the bottle body 12. The chute of the pick and place apparatus preferably includes an induction coil so that when each device is pressed onto a bottle, induction heat is applied to adhere the foil to the bottle. In order to form an effective bond, some pressure needs to be applied to firmly hold the bottle body and neck together during the process. The induction heating and bonding may also be performed in a separate station downstream of the pick and place equipment. ENERCONAHLBRANDT provides suitable induction heating machinery.

The frictional heat generated by the rotation can also be used to fuse the bottle body and neck and cap assembly without the presence of an intermediate foil.

Opening process

When the user reaches the filled bottle, the first step is to remove the cap 50 by lifting the cap at tab 66 to release the seal around the pouring lip and pry the cap off. Now exposing the tab 42. The user inserts a finger into the center of the loop and pulls the loop upward about an axis defined in a plane of the base 20 perpendicular to the legs 40. This produces a rotational movement which scrapes the foil 70 through the longer outer surface of the serrated teeth 36. The location of the teeth facilitates tearing of the foil 70 when the tab is lifted. The tearing of the foil proceeds simultaneously in both clockwise and counter-clockwise directions until it hits the leg 40. Lifting of the loop also breaks the bridges 34 in the frangible regions 32. The portion of foil 70 that is fused to the edge 30 is pulled down and discarded.

The liquid is then poured out through the pour lip 22. When the user wishes to reseal the bottle, the cap 50 is replaced by simply pushing the stopper 54 into the open portion of the neck and pressing downwardly until the corrugations 24, 56 interlock with one another. This sealing is indicated by an audible sound.

Improvements in closure seals

It will be appreciated that a lid seal of the same design may be used with other containers than bottles, such as composite cans. In such an application, the base 20 would need to be modified to fit to a composite can end. This may require an annular flange rather than the depending skirt 44. The flange may then be fused or otherwise attached to the can. In all other respects, the seal is of the same construction.

Claims (10)

1. A thin walled plastic bottle comprising a gas permeable extrusion blow molded body and an injection molded neck and cap assembly adapted to fuse with said body after said body is filled with a liquid, characterized in that: a foil is interposed between said body and said neck and cap means; the cap is fitted to the neck to provide a resealable closure without leakage.

2. A leak-free closure comprising an injection molded neck and cap assembly and a foil, said closure being for use with the body of a thin-walled plastic bottle or other container as claimed in claim 1, wherein: said neck and cap means including a base portion fitted to the body; said foil being sealed to said base of a neck and cap assembly, said neck having a removable annular flange connected to a pull ring and secured to said foil; said removable annular flange being separated from said base by a frangible region; a plurality of associated teeth are formed in the base at or adjacent the frangible region, each tooth having a saw-shaped profile which is inclined inwardly towards the centre of the base, the foil being torn by the teeth on movement of the tab.

3. A closure as claimed in claim 2, wherein: the closure includes a closure plate and a depending skirt, the base having a reduced strength annular groove (48) which is shielded by the closure skirt when the closure is sealed.

4. A closure as claimed in claim 2, wherein: the tab is supported on an annular flange (30) by a pair of adjacent legs (40) to facilitate symmetrical tearing of the foil.

5. A closure as claimed in claim 2, wherein: the foil is a tearable aluminium foil coated on both sides with a layer of meltable polymer material.

6. A bottle comprising a body (2) having an open portion (4), a neck and cap arrangement comprising a skirt portion (44) adapted to fit over the open portion and defining a pour spout (18), and having a pull ring (42) connected to a removable element (30) in a base portion (20) of the neck, the neck resting against an upper surface (12) of the open portion;

a foil is interposed between and fused to the surface (12) and the base (20) such that movement of the tab (42) and the removable element (30) will remove at least a portion of the foil (70) and will open the pour spout (18);

the method is characterized in that: the removable element comprises an annular flange (30) which is separated from the remainder of the base (20) by a frangible groove (32) defining a plurality of associated teeth (36), each tooth having a saw tooth shape which is inclined inwardly towards the centre of the base so that when the tab is pulled, the foil (70) is torn by the teeth (36).

7. A method of bottling a liquid, comprising the steps of:

extrusion blow molding a thin-walled bottle body having an opening;

filling the bottle body;

fitting a neck and cap device, the base of which is covered by a foil and the size of which corresponds to the mouth of the bottle, onto each filled bottle, wherein the cap is fitted to the neck to provide a leak-free resealable closure;

heat sealing the bottle body to the neck and cap device.

8. The method of claim 7, further comprising sterilizing the foil prior to filling.

9. The method of claim 7, wherein: the bottle bodies are blow molded using a rotary machine having a series of molds adapted to pass under a single mold head for supplying a predetermined amount of plastic material to form a parison that is then expanded to form the bottle body.

10. The method of claim 9, wherein: the bottles leaving the mould are sent directly to a filling plant.